10th Sep '25

Multiple Choice 2015-16

Question	Answer	Point
How can the rate of a chemical reaction be calculated?	The rate of a chemical reaction can be found by measuring the quantity of a reactant used or the quantity of product formed over time: mean rate of reaction = quantity of reactant used / time taken OR mean rate of reaction = quantity of product formed / time taken	The rate of a chemical reaction can be found by measuring the quantity of a reactant used or the quantity of product formed over time: mean rate of reaction = quantity of reactant used / time taken OR mean rate of reaction = quantity of product formed / time taken
How is the quantity of a reactant or product measured?	The quantity of reactant or product can be measured by the mass in grams or by a volume in cm3.	The quantity of reactant or product can be measured by the mass in grams or by a volume in cm3.
What are the units for rate of reaction?	The units of rate of reaction may be given as g/s or cm3/s.	The units of rate of reaction may be given as g/s or cm3/s.
(HT only) What is the third unit that is used to measure the rate of reaction in terms of moles?	(HT only) The quantity of reactants in terms of moles and units for rate of reaction in mol/s.	Students are also required to use quantity of reactants in terms of moles and units for rate of reaction in mol/s. (HT only)
What would the total amount of a product formed if the rate of reaction is 4g/s and the reaction continues for 3 minutes?	The total amount of product formed if the rate of reaction is 4g/s and the reaction continues for 3 minutes would be 540g. This is worked out by: 3 x 60 = 180s 4g x 180s = 540g	Students should be able to calculate the mean rate of a reaction from given information about the quantity of a reactant used or the quantity of a product formed and the time taken
What key features must be included for graphs showing the quantity of product formed or quantity of reactant used up against time?	The key features of a graph to show the quantity of product formed or reactant used up would be an appropriate scale, labels with units and a line of best fit excluding anomalies.	Students should be able to draw, and interpret, graphs showing the quantity of product formed or quantity of reactant used up against time
How do you draw a tangent on a curve to measure the rate of a reaction on a graph?	To draw a tangent on a curve to measure the rate of reaction you should find a straight part of the curve of best fit. The slope of the tangent can be used to measure the rate reaction. The steeper the tangent the faster the rate of the reaction.	Students should be able to draw tangents to the curves on these graphs and use the slope of the tangent as a measure of the rate of reaction
(HT only) How do you calculate the gradient of a tangent of a curve from a graph?	(HT only) To calculate the gradient of a tangent: 1. choose any two points on the line. 2. draw a right-angled triangle with the line as hypotenuse. 3. use the scale on each axis to find the triangle's: vertical length. horizontal length. 4. work out the vertical length ÷ horizontal length. 5. the result is the gradient of the line	Students should be able to (HT only) calculate the gradient of a tangent to the curve on these graphs as a measure of rate of reaction at a specific time.
What are the main principals of the collision theory?	Collision theory explains how various factors affect rates of reactions. According to this theory, chemical reactions can occur only when reacting particles collide with each other and with sufficient energy.	Collision theory explains how various factors affect rates of reactions. According to this theory, chemical reactions can occur only when reacting particles collide with each other and with sufficient energy.
What factors can affect the rate of a chemical reaction?	Factors which affect the rates of chemical reactions include: the concentrations of reactants in solution, the pressure of reacting gases, the surface area of solid reactants, the temperature and the presence of catalysts.	Factors which affect the rates of chemical reactions include: the concentrations of reactants in solution, the pressure of reacting gases, the surface area of solid reactants, the temperature and the presence of catalysts.
What does the term activation energy mean?	The minimum amount of energy that particles must have to react is called the activation energy.	The minimum amount of energy that particles must have to react is called the activation energy.
How does increasing the temperature increase the rate of a chemical reaction?	Increasing the temperature increases the frequency of collisions and makes the collisions more energetic, and so increases the rate of reaction.	The minimum amount of energy that particles must have to react is called the activation energy.
How does increasing the pressure of reacting gases affect the rate of a chemical reaction?	Increasing the pressure of reactant gases increases the rate of chemical reactions.	Students should be able to recall how changing the pressure of reacting gases affects the rate of chemical reactions.
How does decreasing the temperature of a chemical reaction affect the rate?	Decreasing the temperature of a chemical reaction decreases the rate of the reaction.	Students should be able to recall how changing the temperature affects the rate of chemical reactions.
How does increasing the surface area to volume ration of a solid reactant affect the rate of a chemical reaction?	Increasing the surface area to volume ratio will increase the rate of the chemical reaction because the there will be more contact between the reactant particles. Increasing the frequency of successful collisions.	Students should be able to predict and explain the effects of changes in the size of pieces of a reacting solid in terms of surface area to volume ratio
How does increasing the concentration of reactants in reacting gases, and the surface solution, the pressure of area of solid reactants increase the rate of a chemical reaction?	Increasing the concentration of reactants in solution, the pressure of reacting gases, and the surface area of solid reactants increases the frequency of collisions and so increases the rate of reaction.	Increasing the concentration increases the frequency of collisions and makes the collisions and so increases the rate of reaction.
How does increasing the concentration of reactants in solution affect the rate of chemical reactions?	Increasing the concentration of reactants in solution increases the rate of chemical reactions.	Students should be able to recall how changing the concentrations of reactants in solution affects the rate of chemical reactions.
How does changing the concentration of a reactant from 1M to 2M affect the rate of a chemical reaction?	When the reactant concentration is 2M there are twice as many particles to react. This means the time it would take for the same number of successful collisions will half.	Students should be able to use simple ideas about proportionality when using collision theory to explain the effect of a factor on the rate of a reaction.
How does increasing the concentration of a solution reactant or the pressure of a gas reactant affect the rate of a chemical reaction?	Increasing the concentration of a solution reactant or the pressure of a gas reactant will increase the rate of a chemical reaction because there would a higher number of particles in the same area, therefore successful collisions between reactants particles will be more frequent, increasing the rate of reaction.	Students should be able to predict and explain using collision theory the effects of changing conditions of concentration, pressure and temperature on the rate of a reaction
How does increasing the surface area of solid reactants affect the rate of a chemical reaction?	Increasing the surface area of solid reactants will increase the rate of a chemical reaction.	Students should be able to recall how changing the surface area of solid reactants affects the rate of chemical reactions.
What are the key characteristics of a catalyst?	Catalysts change the rate of chemical reactions but are not used up during the reaction. Different reactions need different catalysts.	Catalysts change the rate of chemical reactions but are not used up during the reaction. Different reactions need different catalysts.
What is an example of a biological catalyst?	Enzymes act as catalysts in biological systems.	Enzymes act as catalysts in biological systems.
How do catalysts increase the rate of chemical reactions?	Catalysts increase the rate of reaction by providing a different pathway for the reaction that has a lower activation energy.	Catalysts increase the rate of reaction by providing a different pathway for the reaction that has a lower activation energy. * An opportunity to investigate the catalytic effect of adding different metal salts to a reaction such as the decomposition of hydrogen peroxide.
What would the reaction profile for a reaction in the presence of a catalyst look like compared to the same reaction without a catalyst?	The reaction profile for a catalyst would be lower than the pathway for the uncatalysed reaction. The catalyst reaction would be labelled Ea.	A reaction profile for a catalysed reaction can be drawn in the following form: (energy level diagram with reduced Ea with catalyst)
Are catalysts included in the equation for a chemical reaction? Give a reason for your answer.	Catalysts are not included in the chemical equation for a reaction. This is because they are not used up in the chemical reaction.	Students should be able to identify catalysts in reactions from their effect on the rate of reaction and because they are not included in the chemical equation for the reaction.
What is the relationship between catalytic action and activation energy?	The relationship between catalytic action and activation energy is that the more effective the catalyst, the lower the activation energy is.	Students should be able to explain catalytic action in terms of activation energy.
What is the name of the catalyst used in the extraction of aluminium oxide?	The catalyst used in the extraction of aluminium oxide is cryolite.	Students do not need to know the names of catalysts other than those specified in the subject content.
How does the presence of a catalyst affect the rate of a chemical reaction?	The presence of a catalyst increases the rate of a chemical reaction.	Students should be able to recall how the presence of a catalyst affects the rate of chemical reactions.
What equipment would you need to investigate the rate of a chemical reaction?	Equipment you would need to investigate the rate of a chemical reaction: timer / stop watch measuring cylinder reactants balance gas syringe if product is a gas balance conical flask	Required practical 5 - rates of reaction (developing a hypothesis) (AT skills 1,3,5,6)
What is a reversible reaction?	A reversible reaction is one where the products of the reaction can react to produce the original reactants.	In some chemical reactions, the products of the reaction can react to produce the original reactants.
How can reversible reactions be represented?	Reversible reactions can be represented by: A B (reversible arrow) C D	Such reactions are called reversible reactions and are represented: A B (reversible arrow) C D
If the reversible reaction below was heated which direction would it react? Ammonium chloride (reversible arrow) ammonia hydrogen chloride	If the reversible reaction of ammonium chloride was heated it would decompose to produce ammonia and hydrogen chloride.	For example: ammonium chloride (heat - reversible arrow - cool) ammonia hydrogen chloride.
If a reversible reaction is exothermic in one direction, what is it in the opposite direction?	If a reversible reaction is exothermic in one direction, it is endothermic in the opposite direction.	If a reversible reaction is exothermic in one direction, it is endothermic in the opposite direction.
If 3500 KJ of energy is transferred in the forward reaction, how much energy would be transferred in the reverse reaction?	In a reversible reaction the same amount of energy is transferred in each case so 3500 KJ would be transferred in the reverse reaction.	In a reversible reaction the same amount of energy is transferred in each case. For example: hydrated copper sulfate [blue] (endothermic - reversible arrow - exothermic) anhydrous copper sulfate [white] water.
How can the direction of reversible reactions be changed?	The direction of reversible reactions can be changed by changing the conditions such as temperature and pressure of gases.	The direction of reversible reactions can be changed by changing the conditions.
What would happen if the temperature was increased for the reaction below: N2(g) 3H2(g) (reversible reaction) 2NH3(g) The forward reaction is exothermic.	If the temperature is increased, then the equilibrium will shift to the left (the endothermic direction), to remove the extra heat added. This is why only a moderately high temperature (380 - 450°C) is used in the Haber process.	If the temperature of a system at equilibrium is increased: - the relative amount of products at equilibrium increases for an endothermic reaction - the relative amount of products at equilibrium decreases for an exothermic reaction.
What would happen if the temperature was decreased for the reaction below: N2(g) 3H2(g) (reversible reaction) 2NH3(g) The forward reaction is exothermic.	If the temperature is decreased, then the equilibrium will shift to the right (the exothermic direction), to produce additional heat.	If the temperature of a system at equilibrium is decreased: - the relative amount of products at equilibrium decreases for an endothermic reaction - the relative amount of products at equilibrium increases for an exothermic reaction.
Does increasing the temperature of a reaction favor the endothermic or exothermic reaction?	Increasing the temperature always favours the endothermic reaction. Decreasing the temperature always favours the exothermic reaction	Students should be able to interpret appropriate given data to predict the effect of a change in temperature on given reactions at equilibrium.
What does the term equilibrium mean?	When a reversible reaction occurs in apparatus which prevents the escape of reactants and products, equilibrium is reached when the forward and reverse reactions occur at exactly the same rate.	When a reversible reaction occurs in apparatus which prevents the escape of reactants and products, equilibrium is reached when the forward and reverse reactions occur at exactly the same rate.
How does increasing and decreasing the pressure for gaseous reactions at equilibrium?	For gaseous reactions at equilibrium: - an increase in pressure causes the equilibrium position to shift towards the side with the smaller number of molecules as shown by the symbol equation for that reaction - a decrease in pressure causes the equilibrium position to shift towards the side with the larger number of molecules as shown by the symbol equation for that reaction.	For gaseous reactions at equilibrium: ? an increase in pressure causes the equilibrium position to shift towards the side with the smaller number of molecules as shown by the symbol equation for that reaction ? a decrease in pressure causes the equilibrium position to shift towards the side with the larger number of molecules as shown by the symbol equation for that reaction.
When does changing the pressure of gaseous reactions not affect the equilibrium?	Changes in pressure will not affect the position of equilibrium, if the number of moles of gases on both sides of the equation are equal. Remember, liquids and solids contribute nothing to the volume of the equilibrium mixture.	Students should be able to interpret appropriate given data to predict the effect of pressure changes on given reactions at equilibrium.
What does the relative amounts of all the reactants and products at equilibrium depend on?	The relative amounts of all the reactants and products at equilibrium depend on the conditions of the reaction.	The relative amounts of all the reactants and products at equilibrium depend on the conditions of the reaction.
What happens when a system is at equilibrium and a change is made to the conditions?	If a system is at equilibrium and a change is made to any of the conditions, then the system responds to counteract the change.	If a system is at equilibrium and a change is made to any of the conditions, then the system responds to counteract the change.
What is Le Chatelier's principle used for?	The effects of changing conditions on a system at equilibrium can be predicted using Le Chatelier's Principle.	The effects of changing conditions on a system at equilibrium can be predicted using Le Chatelier's Principle.
How would changing the conditions of the equation below effect the equilibrium? A(g) 2B (g) (reversible arrow) C(g) D(g) a) increasing concentration of A b) increasing the pressure of the reactants c) increasing the temperature of the reaction (the forward reaction is exothermic)	Changing the conditions of the equation below would have the following effects on the equilibrium: A(g) 2B (g) (reversible arrow) C(g) D(g) a) equilibrium would shift to the right to reduce the amount of A particles b) equilibrium would shift to the right as there are fewer gas molecules in the products than in the reactants c) equilibrium would shift to the left as the reaction tries to cool itself down again	Students should be able to make qualitative predictions about the effect of changes on systems at equilibrium when given appropriate information.
What happens when the concentration of one of the reactions or products in an equilibrium system is changed?	If the concentration of one of the reactants or products is changed, the system is no longer at equilibrium and the concentrations of all the substances will change until equilibrium is reached again.	If the concentration of one of the reactants or products is changed, the system is no longer at equilibrium and the concentrations of all the substances will change until equilibrium is reached again.
What happens when the concentration of a reactant is increased in an equilibrium system?	If the concentration of a reactant is increased, more products will be formed until equilibrium is reached again.	If the concentration of a reactant is increased, more products will be formed until equilibrium is reached again.
What happens when the concentration of a reactant is decreased in an equilibrium system?	If the concentration of a product is decreased, more reactants will react until equilibrium is reached again.	If the concentration of a product is decreased, more reactants will react until equilibrium is reached again.
What would happen if the concentration of potassium chloride is increase? Cl2(g) H2O(l) (reversible arrow) Cl-(aq) ClO-(aq) 2H (aq)	If potassium chloride (a source of chloride ions) is added to the equilibrium mixture, the equilibrium will shift to the left, to remove the chloride ions added.	Students should be able to interpret appropriate given data to predict the effect of a change in concentration of a reactant or product on given reactions at equilibrium.
The Haber process is used to manufacture what substance?	The Haber process is used to manufacture ammonia, which can be used to produce nitrogen-based fertilisers.	The Haber process is used to manufacture ammonia, which can be used to produce nitrogen-based fertilisers.
Write a word equation for the Haber process?	Nitrogen Hydrogen <=> Ammonia	Some of the hydrogen and nitrogen reacts to form ammonia.
Why does some of the ammonia produced through the Haber process break back down into nitrogen and hydrogen?	Because the reaction is a reversible reaction.	The reaction is reversible so some of the ammonia produced breaks down into nitrogen and hydrogen: nitrogen hydrogen --> <-- ammonia
Explain how the commercially used conditions for the Haber process are related to the availability and cost of raw materials?	The raw materials for this process are hydrogen and nitrogen. Hydrogen is obtained by reacting natural gas - methane - with steam, or through the cracking of oil. This pathway is used as hydrocarbon compounds contain large percentages of hydrogen and are readily available. Nitrogen is obtained by burning hydrogen in air. Air is used due to being rich in Nitrogen gas (79% nitrogen); nearly all the rest is oxygen. When hydrogen is burned in air, the oxygen combines with the hydrogen, leaving nitrogen behind.	? explain how the commercially used conditions for the Haber process are related to the availability and cost of raw materials and energy supplies, control of equilibrium position and rate
How is any ammonia created through the Haber process separated from any unreacted nitrogen and hydrogen?	The remaining products are cooled. Ammonia has a much higher boiling point than either hydrogen or nitrogen, so liquefies and is removed. The remaining hydrogen and nitrogen gases are recycled.	On cooling, the ammonia liquefies and is removed. The remaining hydrogen and nitrogen are recycled.
Justify why the Haber process is carried out at 200 atmospheres?	The Haber process is a reversible reaction meaning it will reach a dynamic equilibrium As there are fewer molecules of product than reactant, high pressure pushes equilibrium to favour the products and produce a higher yield of ammonia. The reason pressures higher than 200 atmospheres are not used - Substances under extremely high pressure can be dangerous. - Extremely expensive equipment must be used to keep reactants under sustained high pressures. - High amounts of energy are required to pressurise the gas.	MS 1a Recognise and use expressions in decimal form. MS 1c Use ratios, fractions and percentages.
Justify the use of a high temperature in the Haber process?	The Haber process is a reversible reaction meaning it will reach a dynamic equilibrium The forward reaction is exothermic, so in fact a higher temperature reduces the yield of ammonia. The reason that higher temperatures are used are to increase the rate of reaction, to make the process economically viable.	? apply the principles of dynamic equilibrium in Reversible reactions and dynamic equilibrium to the Haber process
Suggest why a catalyst is used in the Haber process?	The Haber process is a reversible reaction meaning it will reach a dynamic equilibrium. The use of a catalyst does not affect the position of equilibrium, but will speed up the rate at which it reaches equilibrium.	? explain the trade-off between rate of production and position of equilibrium
What are the raw materials required for the Haber process?	The raw materials for the Haber process are nitrogen and hydrogen	The raw materials for the Haber process are nitrogen and hydrogen
What is commonly used as the source of nitrogen in the Haber process? What is commonly used as the source of hydrogen in the Haber process?	Nitrogen gas used in the reaction is taken from the air by reacting the oxygen in the air with hydrogen, leaving nearly pure hydrogen gas. Hydrogen for the reaction is created by reacting natural gas (mostly methane) and steam.	Students should be able to recall a source for the nitrogen and a source for the hydrogen used in the Haber process
What conditions are used in the Haber process?	- Iron catalyst - High temperature (450C) - High pressure (200 atmospheres)	The purified gases are passed over a catalyst of iron at a high temperature (about 450?C) and a high pressure (about 200 atmospheres).
Where does crude oil come from?	Crude oil is a finite resource found in rocks. Crude oil is the remains of an ancient biomass consisting mainly of plankton that was buried in mud.	Crude oil is a finite resource found in rocks. Crude oil is the remains of an ancient biomass consisting mainly of plankton that was buried in mud.
Is crude oil a mixture of elements, compounds or both?	Crude oil is a mixture of a very large number of compounds called hydrocarbons.	Crude oil is a mixture of a very large number of compounds.
What is the definition of a hydrocarbon?	Hydrocarbons are molecules made up of hydrogen and carbon atoms only.	Most of the compounds in crude oil are hydrocarbons, which are molecules made up of hydrogen and carbon atoms only.
Does crude oil contain mostly alkanes or alkenes?	Most of the hydrocarbons in crude oil are hydrocarbons called alkanes	Most of the hydrocarbons in crude oil are hydrocarbons called alkanes. The general formula for the homologous series of alkanes is CnH2n+2
What are the names of the first four members of alkanes?	The first four members of the alkanes are: methane, ethane, propane and butane.	The first four members of the alkanes are methane, ethane, propane and butane.
What is the general formula for alkane molecules?	The general formula for the homologous series of alkanes is CnH2n 2.	Alkane molecules can be represented in the following forms: C2H6 or displayed formula.
Which of the following are examples of alkanes: C4H10, C2H4, C5H12?	C4H10 and C5H12 are both examples of alkanes.	Students should be able to recognise substances as alkanes given their formulae in these forms.
Name the alkane with: a) 1 carbon b) 2 carbons c) 3 carbons d) 4 carbons	a) Methane b) Ethane c) Propane d) Butane	Students do not need to know the names of specific alkanes other than methane, ethane, propane and butane.
How can crude oil be separated into fractions?	The many hydrocarbons in crude oil may be separated into fractions, each of which contains molecules with a similar number of carbon atoms, by fractional distillation.	The many hydrocarbons in crude oil may be separated into fractions, each of which contains molecules with a similar number of carbon atoms, by fractional distillation.
Why is it useful to separate crude oil into fractions?	The fractions can be processed to produce fuels and feedstock for the petrochemical industry.	The fractions can be processed to produce fuels and feedstock for the petrochemical industry.
What type of fuels are produced from crude oil?	Many of the fuels on which we depend for our modern lifestyle, such as petrol, diesel oil, kerosene, heavy fuel oil and liquefied petroleum gases, are produced from crude oil.	Many of the fuels on which we depend for our modern lifestyle, such as petrol, diesel oil, kerosene, heavy fuel oil and liquefied petroleum gases, are produced from crude oil.
What are three examples of useful materials produced by the petrochemical industry?	Many useful materials on which modern life depends are produced by the petrochemical industry, such as solvents, lubricants, polymers, detergents.	Many useful materials on which modern life depends are produced by the petrochemical industry, such as solvents, lubricants, polymers, detergents.
Why is it possible to produce such a vast array of products from crude oil?	The vast array of natural and synthetic carbon compounds occur due to the ability of carbon atoms to form families of similar compounds.	The vast array of natural and synthetic carbon compounds occur due to the ability of carbon atoms to form families of similar compounds.
How does fractional distillation separate crude oil into fractions?	Fractional distillation seperates crude oil first by vaporisating all compounds, a column of varying temperatures allows molecules with similar condensation points to be seperated. This is due to their carbon chain length	Students should be able to explain how fractional distillation works in terms of evaporation and condensation.
What factor of effects a hydrocarbons boiling point, viscosity and flammability?	The factor that effects a hydrocarbons boiling point, viscosity and flammability is the size of their molecule	Some properties of hydrocarbons depend on the size of their molecules, including boiling point, viscosity and flammability. These properties influence how hydrocarbons are used as fuels. (WS) Investigate the properties of different hydrocarbons.
How does boiling point, viscosity and flammability change with increasing molecular size?	As molecular size of hydrocarbons increases the boiling point increases, the viscosity increases and flammability decreases.	Students should be able to recall how boiling point, viscosity and flammability change with increasing molecular size.
What are the products of the complete combustion?	The complete combustion of a hydrocarbon produces carbon dioxide and water.	The complete combustion of a hydrocarbon produces carbon dioxide and water.
What is the balanced symbol equation for the complete combustion of methane (CH4)? (include state symbols in your answer)	CH4(g) + O2(g) -> CO2(g) + H2O(g)	Students should be able to write balanced equations for the complete combustion of hydrocarbons with a given formula.
What happens to the carbon and hydrogen atoms during combustion reactions?	During combustion, the carbon and hydrogen in the fuels are oxidised.	During combustion, the carbon and hydrogen in the fuels are oxidised.
What is the useful outcome of the combustion of hydrocarbon fuels?	The useful outcome of the combustion of hydrocarbon fuels is that it releases energy.	The combustion of hydrocarbon fuels releases energy.
Describe how the each of the following properties changes as the length of hydrocarbon chains within a fraction increases: a) Boiling point b) Flammability c) Viscosity	a) Boiling point increases as chain length increases. b) Flammability decreases as chain length increases. c) Viscosity increases as chain length increases.	Knowledge of trends in properties of hydrocarbons is limited to: ? boiling points, ? viscosity, ? flammability.
What is cracking?	Cracking is when hydrocarbons are broken down into smaller more useful molecules	Hydrocarbons can be broken down (cracked) to produce smaller, more useful molecules.
Describe the conditions required for catalytic cracking?	Hydrocarbons are heated to vaporise them and passed through a hot catalyst breaking down the molecules into smaller ones by thermal decomposition	Cracking can be done by various methods including catalytic cracking and steam cracking.
How is cracking done using steam?	Hydrocarbons are heated to vaporise them and mixed with steam and heated to very high temperatures breaking down the molecules into smaller ones by thermal decomposition	Students should be able to describe in general terms the conditions used for catalytic cracking and steam cracking.
What are the products of cracking?	The products of cracking include alkanes and another type of hydrocarbon called alkenes.	The products of cracking include alkanes and another type of hydrocarbon called alkenes.
What is the balanced equation for the cracking of this alkane? C15H32 --> 2C2H4 C3H6 _______	The balanced equation for the cracking is: C15H32 --> 2C2H4 + C3H6 + C8H18	Students should be able to balance chemical equations as examples of cracking given the formulae of the reactants and products.
Why do do alkenes react with bromine water, but alkanes don't?	Alkenes react with bromine water because they have a C=C making them more reactive than alkanes (which don?t react with bromine water)	Alkenes are more reactive than alkanes and react with bromine water, which is used as a test for alkenes.
What is the chemical test and positive result for identifying alkenes?	The chemical test for identifying alkenes is to add bromine water, the positive result is that the bormine was decolourises.	Students should be able to recall the colour change when bromine water reacts with an alkene.
Why is cracking of hydrocarbons so important?	Cracking is important because there is a high demand for fuels with small molecules and so some of the products of cracking are useful as fuels.	There is a high demand for fuels with small molecules and so some of the products of cracking are useful as fuels.
How are alkenes used in chemical industry?	Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.	Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.
How does modern life depend on the uses of hydrocarbons?	Hydrocarbons are used to produce fuels for transport, generating electricity. They are the raw materials for producing plastics and other chemicals.	Students should be able to give examples to illustrate the usefulness of cracking. They should also be able to explain how modern life depends on the uses of hydrocarbons. (For Combined Science: Trilogy and Synergy students do not need to know the formulae or names of individual alkenes.)
What is the structure of an alkene like?	Alkenes are hydrocarbons (molecules made up of only hydrogen and carbon) with a double carbon-carbon bond.	Alkenes are hydrocarbons with a double carbon-carbon bond.
What is the general formula for the homologous series of alkenes?	The general formula for the homologous series of alkenes is CnH2n.	The general formula for the homologous series of alkenes is CnH2n. Recognise substances that are alkenes from their names or from given formulae in these forms.
Why are alkene molecules called unsaturated molecules?	Alkene molecules are unsaturated because they contain two fewer hydrogen atoms than the alkane with the same number of carbon atoms.	Alkene molecules are unsaturated because they contain two fewer hydrogen atoms than the alkane with the same number of carbon atoms.
What are the conditions for the addition of water to alkenes?	The conditions for the additional of water to alkenes is to use steam passed over a catalyst of hot phosphoric acid. The resulting product is an alcohol.	Students should be able to describe the reactions and conditions for the addition of water alkenes
What are the conditions for the addition of halogens to alkenes?	If the alkene is a gas the halogen must also be a gas. If the alkene is a liquid then the halogen can be bubbled through as a gas.	Students should be able to describe the reactions and conditions for the addition of halogens to alkenes
What are the names of the first four members of the homologous series of alkenes?	The first four members of the homologous series of alkenes are ethene, propene, butene and pentene.	The first four members of the homologous series of alkenes are ethene, propene, butene and pentene.
What is the structural and display formula ethene?	The structural formula for ethene is C2H4, display formula shows C=C with 2 hydrogens bonded to each C by a single bond.	Alkene molecules can be represented in the following forms: C3H6 or displayed formula
What is the structural and display formula pentene?	The structural formula for ethene is C5H10, display formula shows one C=C anywhere with all other carbons single bonded C-C. There are 10 carbons single bonded, each carbon has four bonds in total.	Students do not need to know the names of individual alkenes other than ethene, propene, butene and pentene.
What is the functional group for alkenes?	Alkenes are hydrocarbons with the functional group C=C.	Alkenes are hydrocarbons with the functional group C=C.
What determines the reactions of organic compounds?	It is the generality of reactions of functional groups that determine the reactions of organic compounds.	It is the generality of reactions of functional groups that determine the reactions of organic compounds.
How does the combustion of alkenes differ in oxygen and in air?	Alkenes react with oxygen in combustion reactions in the same way as other hydrocarbons, but they tend to burn in air with smoky flames because of incomplete combustion.	Alkenes react with oxygen in combustion reactions in the same way as other hydrocarbons, but they tend to burn in air with smoky flames because of incomplete combustion.
How do alkenes react with hydrogen, water and the halogens?	Alkenes react with hydrogen (in the presence of a nickel catalyst), water (phosphoric acid catalyst) and the halogens, by the addition of atoms across the carbon-carbon double bond so that the double bond becomes a single carbon-carbon bond.	Alkenes react with hydrogen, water and the halogens, by the addition of atoms across the carbon-carbon double bond so that the double bond becomes a single carbon-carbon bond.
What are the conditions required for the addition of hydrogen to alkenes?	The conditions for the addition of hydrogen to alkenes is 300oC and over a heated catalyst of finely divided nickel	Students should be able to describe the reactions and conditions for the addition of hydrogen to alkenes
What are the conditions required for the addition of water to alkenes?	The conditions for the addition of water to alkenes is high temperature (for steam) and a phosphoric acid catalyst.	Students should be able to describe the reactions and conditions for the addition of hydrogen to alkenes
What are the structures of the following products of alkene addition reactions: 1. dibromoethane 2. dichloroethane 3. ethanol 4. ethane	The structures of the following products of alkene addition reactions are: 1. dibromoethane = CH2BrCH2Br 2. dichloroethane = CH2ClCH2Cl 3. ethanol = C2H5OH 4. ethane = C2H6	Students should be able to draw fully displayed structural formulae of the first four members of the alkenes and the products of their addition reactions with hydrogen, water, chlorine, bromine and iodine.
What is the functional group for alochols?	Alcohols contain the functional group -OH.	Alcohols contain the functional group ?OH.
What are the names of the first four members of the homologous series of alcohols?	Methanol, ethanol, propanol and butanol are the first four members of a homologous series of alcohols.	Methanol, ethanol, propanol and butanol are the first four members of a homologous series of alcohols. Opportunities when investigating reactions of alcohols.
What are the names and structural formula for the first four members of the homologous series of alcohols?	The structural formula for the first four members of the homologous series of alochols are: methanol = CH3OH ethanol = CH3CH2OH propanol = CH3CH2CH2OH butanol = CH3CH2CH2CH2OH	Alcohols can be represented in the following forms: CH3CH2OH or displayed formula
What happens when when alochols react with sodium?	When alcohols react with sodium they produce hydrogen gas	Students should be able to describe what happens when any of the first four alcohols react with sodium
Name the following alcohols from their formula: a) C2H5OH b) C3H7OH c) C6H11OH	a) Ethanol b) Propanol c) Hexanol	Students should be able to recognise alcohols from their names from given formulae.
What happens when when alochol burns in air?	When alcohols are burnt in air they combust to form water and carbon dioxide, releasing energy	Students should be able to describe what happens when any of the first four alcohols react with burn in air
What pH solutions are formed when alcohols are added to water?	When alcohols are added to water they form a neutral solution (OH- and XH )	Students should be able to describe what happens when any of the first four alcohols are added to water
What are the main uses of alcohols?	The main uses of alochols are fuels, producing alocholic drinks, cleaning products, making esters	Students should be able to recall the main uses of these alcohols.
How can ethanol be produced from sugar?	Aqueous solutions of ethanol are produced when sugar solutions are fermented using yeast.	Aqueous solutions of ethanol are produced when sugar solutions are fermented using yeast.
What are the conditions used during the fermentation of sugar to produce ethanol?	Fermintation of ethanol from sugar requires water, enzymes from yeast, temperature between 25-40 degress celcius and an absence of oxygen	Students should know the conditions used for fermentation of sugar using yeast.
What happens when alcohols react with oxidising agents?	When alochols react with oxidising agents they form carboxylic acids	Students should be able to describe what happens when any of the first four alcohols react with an oxidising agent
What is the functional group for carboxylic acids?	Carboxylic acids have the functional group COOH.	Carboxylic acids have the functional group ?COOH.
What are the names of the first four members of a homologous series of carboxylic acids?	The first four members of a homologous series of carboxylic acids are methanoic acid, ethanoic acid, propanoic acid and butanoic acid	The first four members of a homologous series of carboxylic acids are methanoic acid, ethanoic acid, propanoic acid and butanoic acid. (WS) Opportunies within investigation of the reactions of carboxylic acids.
What is the structure of the first four members of a homologous series of carboxylic acids?	the structure of the first four members of a homologous series of carboxylic acids are: 1. methanoic acid = HCOOH 2. ethanoic acid = CH2COOH 3. propanoic acid = C2H5COOH 4. butanoic acid = C3H7COOH	The structures of carboxylic acids can be represented in the following forms: CH3COOH or displayed formula
What are the names of the following carboxylic acids? 1. HCOOH 2. CH2COOH 3. C2H5COOH 4. C3H7COOH	the structure of the first four members of a homologous series of carboxylic acids are: 1. methanoic acid = HCOOH 2. ethanoic acid = CH2COOH 3. propanoic acid = C2H5COOH 4. butanoic acid = C3H7COOH	Students should be able to recognise carboxylic acids from their names or from given formulae.
(HT only) Why are carboxylic acids weak acids in terms of ionisation and pH?	Carboxylic acids are weak acids as they exist in an equlibrium so don't ever fully ionise (dissossiate)	(HT only) explain why carboxylic acids are weak acids in terms of ionisation and pH (see Strong and weak acids
What happens when carboxylic acids react with carbonates?	When carboxylic acids react with carbonates they product carbon dioxide gas	Students should be able to describe what happens when any of the first four carboxylic acids react with carbonates
What happens when carboxylic acids dissolve in water?	When carboxylic acids dissolve in water they produce acidic solutions	Students should be able to describe what happens when any of the first four carboxylic acids dissolve in water
What happens when carboxylic acids react with alcohols?	When carboxylic acids react with alochols they produce an ester and water. An acid catalyst is needed.	Students should be able to describe what happens when any of the first four carboxylic acids react with alcohols.
What is a pure substance?	A pure substance is a single element or compound, not mixed with any other substance.	In chemistry, a pure substance is a single element or compound, not mixed with any other substance.
What is a formulation?	A formulation is a mixture that has been designed to have distinct properties and be used as a useful product.	A formulation is a mixture that has been designed as a useful product.
What can be used to distinguish between pure substances and mixtures?	Use Melting point and boiling point data to distinguish between pure substances and mixtures?	Pure elements and compounds melt and boil at specific temperatures. Melting point and boiling point data can be used to distinguish pure substances from mixtures.
What are examples of formulations?	Formulations: fuels, cleaning agents, paints, medicines, alloys, fertilisers and foods.	Formulations include fuels, cleaning agents, paints, medicines, alloys, fertilisers and foods.
What is a pure substance in everyday language?	A pure substance can mean a substance that has had nothing added to it, so it is unadulterated and in its natural state, eg pure milk.	In everyday language, a pure substance can mean a substance that has had nothing added to it, so it is unadulterated and in its natural state, eg pure milk.
How are formulations made?	They are made by mixing the components in carefully measured quantities to ensure that the product has the required properties.	Formulations are made by mixing the components in carefully measured quantities to ensure that the product has the required properties.
How would you test if carbon dioxide was present In a reaction?	Use an aqueous solution of calcium hydroxide (lime water). When carbon dioxide is shaken with or bubbled through limewater the limewater turns milky (cloudy).	The test for carbon dioxide uses an aqueous solution of calcium hydroxide (lime water). When carbon dioxide is shaken with or bubbled through limewater the limewater turns milky (cloudy).
How would you test if Hydrogen was present In a reaction?	Use a burning splint held at the open end of a test tube of the gas. Hydrogen burns rapidly with a pop sound	The test for hydrogen uses a burning splint held at the open end of a test tube of the gas. Hydrogen burns rapidly with a pop sound
How would you test if chlorine was present In a reaction?	When damp litmus paper is put into chlorine gas the litmus paper is bleached and turns white.	The test for chlorine uses litmus paper. When damp litmus paper is put into chlorine gas the litmus paper is bleached and turns white.
How would you test if Oxygen was present In a reaction?	Use a glowing splint inserted into a test tube of the gas. The splint relights in oxygen	The test for oxygen uses a glowing splint inserted into a test tube of the gas. The splint relights in oxygen
What can Chromatography be used to separate?	Chromatography can be used to separate mixtures such as inks and can give information to help identify the substances from which it is made.	Chromatography can be used to separate mixtures and can give information to help identify substances.
What are the names of the two phases involved in chromatography?	Stationary phase and mobile phase.	Chromatography involves a stationary phase and a mobile phase.
What does seperation depend on?	Separation depends on the distribution of substances between the phases.	Separation depends on the distribution of substances between the phases
How should the Rf value be expressed?	The ratio of the distance moved by a compound (centre of spot from origin) to the distance moved by the solvent	The ratio of the distance moved by a compound (centre of spot from origin) to the distance moved by the solvent can be expressed as its R value
How is the Rf value calculated?	Rf = distance moved by substance / distance moved by solvent	RT = distance moved by substance / distance moved by solvent
How do the Rf values of compounds change in different solvents?	Different compounds have different R values in different solvents.	Different compounds have different R values in different solvents,
How can compounds be identified?	Rf values can be used to help identify the compounds.	Rf values can be used to help identify the compounds.
How many spots are produced by a pure compound compared to a compound in a mixture?	The compounds in a mixture may separate into different spots depending on the solvent but a pure compound will produce a single spot in all solvents.	The compounds in a mixture may separate into different spots depending on the solvent but a pure compound will produce a single spot in all solvents.
How can paper chromatography be used to separate mixtures?	A spot of each mixture is dropped onto the start line of the paper chromotography. The paper chromatogram is introduced to a solvent and left for seperation to take place.	Students should be able to explain how paper chromatography separates mixtures
How can chromatographic methods can be used for distinguishing pure substances from impure substances?	The compounds in a mixture may separate into multiple spots depending on the solvent, but a pure substance will always produce a single spot in all solvents.	Students should be able to suggest how chromatographic methods can be used for distinguishing pure substances from impure substances
How can chromatograms be used to determine R values?	The R value can be calculated and compared. RT = distance moved by substance / distance moved by solvent	Students should be able to interpret chromatograms and determine R values from chromatograms
How can elements and compounds be detected?	Elements and compounds can be detected and identified using instrumental methods. Instrumental methods are accurate, sensitive and rapid.	Elements and compounds can be detected and identified using instrumental methods. Instrumental methods are accurate, sensitive and rapid.
What are the advantages of instrumental methods compared with the chemical tests?		Students should be able to state advantages of instrumental methods compared with the chemical tests in this specification.
What are the different colours produced by some metal ions (cations)?	lithium compounds result in a crimson flame ? sodium compounds result in a yellow flame ? potassium compounds result in a lilac flame ? calcium compounds result in an orange-red flame ? copper compounds result in a green flame.	Flame tests can be used to identify some metal ions (cations). Lithium, sodium, potassium, calcium and copper compounds produce distinctive colours in flame tests: ? lithium compounds result in a crimson flame ? sodium compounds result in a yellow flame ? potassium compounds result in a lilac flame ? calcium compounds result in an orange-red flame ? copper compounds result in a green flame.
When are some flame colours masked?	If a sample containing a mixture of ions	If a sample containing a mixture of ions is used some flame colours can be masked
How do carbonates react with dilute acids?	Carbonates react with dilute acids to form carbon dioxide gas. Carbon dioxide can be identified with limewater.	Carbonates react with dilute acids to form carbon dioxide gas. Carbon dioxide can be identified with limewater.
What do Halide ions produce when they react with silver nitrate solution?	Halide ions in solution produce precipitates with silver nitrate solution in the presence of dilute nitric acid. Silver chloride is white, silver bromide is cream and silver iodide is yellow.	Halide ions in solution produce precipitates with silver nitrate solution in the presence of dilute nitric acid. Silver chloride is white, silver bromide is cream and silver iodide is yellow.
What do Sulfate ions in solution produce when they react with barium chloride in the presence of hydrochloric acid?	Sulfate ions in solution produce a white precipitate with barium chloride solution in the presence of dilute hydrochloric acid.	Sulfate ions in solution produce a white precipitate with barium chloride solution in the presence of dilute hydrochloric acid.
What solution can be used to identify some some metal ions (cations)?	Sodium hydroxide solution can be used to identify some metal ions (cations).	Sodium hydroxide solution can be used to identify some metal ions (cations).
What do solutions of aluminium, calcium and magnesium ions form?	They form white precipitates when sodium hydroxide solution is added but only the aluminium hydroxide precipitate dissolves in excess sodium hydroxide solution.	Solutions of aluminium, calcium and magnesium ions form white precipitates when sodium hydroxide solution is added but only the aluminium hydroxide precipitate dissolves in excess sodium hydroxide solution.
What happens when sodium hydroxide is added to Solutions of copper(II), iron(II) and iron(III) ions?	Solutions of copper(II), iron(II) and iron(III) ions form coloured precipitates when sodium hydroxide solution is added. Copper(II) forms a blue precipitate, iron(II) a green precipitate and iron(III) a brown precipitate.	Solutions of copper(II), iron(II) and iron(III) ions form coloured precipitates when sodium hydroxide solution is added. Copper(II) forms a blue precipitate, iron(II) a green precipitate and iron(III) a brown precipitate.
Write a balanced equation for reactions that produce the insoluble hydroxides.	CuSo4 2NaOH Cu(OH)2 Na2SO4	Students should be able to write balanced equations for the reactions to produce the insoluble hydroxides.
What is Flame emission spectroscopy used for?	Flame emission spectroscopy is an example of an instrumental method used to analyse metal ions in solutions.	Flame emission spectroscopy is an example of an instrumental method used to analyse metal ions in solutions.
What can the output of a line spectrum be used for?	The sample is put into a flame and the light given out is passed through a spectroscope. The output is a line spectrum that can be analysed to identify the metal ions in the solution and measure their concentrations.	The sample is put into a flame and the light given out is passed through a spectroscope. The output is a line spectrum that can be analysed to identify the metal ions in the solution and measure their concentrations.
What is the composition of the earths atmosphere?	about four-fifths (approximately 80 %) nitrogen ? about one-fifth (approximately 20 %) oxygen ? small proportions of various other gases, including carbon dioxide, water vapour and noble gases.	Students to recall current composition of the earths atmosphere: about four-fifths (approximately 80 %) nitrogen, about one-fifth (approximately 20 %) oxygen and small proportions of various other gases, including carbon dioxide, water vapour and noble gases.
How has the Earths atmosphere evolved?	One theory suggests that during the first billion years of the Earth?s existence there was intense volcanic activity that released gases that formed the early atmosphere and water vapour that condensed to form the oceans. At the start of this period the Earth?s atmosphere may have been like the atmospheres of Mars and Venus today, consisting of mainly carbon dioxide with little or no oxygen gas.	Students should be able to, given appropriate information, interpret evidence and evaluate different theories about the Earth's early atmosphere.
How has the Earths atmosphere evolved?	One theory suggests that during the first billion years of the Earth?s existence there was intense volcanic activity that released gases that formed the early atmosphere and water vapour that condensed to form the oceans. At the start of this period the Earth?s atmosphere may have been like the atmospheres of Mars and Venus today, consisting of mainly carbon dioxide with little or no oxygen gas.	One theory suggests that during the first billion years of the Earth's existence there was intense volcanic activity that released gases that formed the early atmosphere and water vapour that condensed to form the oceans. At the start of this period the Earth's atmosphere may have been like the atmospheres of Mars and Venus today, consisting of mainly carbon dioxide with little or no oxygen gas.
What types of gases did volcanoes produce?	Volcanoes produced nitrogen which gradually built up in the atmosphere and there may have been small proportions of methane and ammonia.	Volcanoes also produced nitrogen which gradually built up in the atmosphere and there may have been small proportions of methane and ammonia.
What happened to the atmopshere when the oceans formed?	When the oceans formed carbon dioxide dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of carbon dioxide in the atmosphere.	When the oceans formed carbon dioxide dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of carbon dioxide in the atmosphere. No knowledge of other theories is required.
What process has caused oxygen levels in our atmosphere to increase since its formation?	Photosynthesis, carried out by organisms such as algae and plants converted carbon dioxide into the oxygen now found in the atmosphere.	Algae and plants produced the oxygen that is now in the atmosphere by photosynthesis, which can be represented by the equation.
When did Algae first produce oxygen?	Algae first produced oxygen about 2.7 billion years ago and soon after this oxygen appeared in the atmosphere. Over the next billion years plants evolved and the percentage of oxygen gradually increased to a level that enabled animals to evolve.	Algae first produced oxygen about 2.7 billion years ago and soon after this oxygen appeared in the atmosphere. Over the next billion years plants evolved and the percentage of oxygen gradually increased to a level that enabled animals to evolve.
How did Algae and plants affect the atmosphere?	Algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis.	Algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis.
Apart from through the process of photosynthesis, what else has caused carbon dioxide levels in the atmosphere to decrease since its formation?	Carbon dioxide levels also decreased due to some dissolving into the oceans, the formation of sedimentary rocks and the formation of fossil fuels.	Carbon dioxide was also decreased by the formation of sedimentary rocks and fossil fuels that contain carbon.
How did the Earth's atmosphere change over time? Why did these changes happen?	Volcanic activity caused high levels of carbon dioxide, as the volancos died out the Earth's temperature cooled. The water vapour produced by volcanos condensed to form oceans. The carbon dioxide levels decreased as it dissolved into the oceans and formed part of the shells of marine animals.	Students should be able to describe the main changes in the atmosphere over time and some of the likely causes of these changes
How and why did limestone, coal, crude oil and natural gas form?	Limestone, crude oil and natural gas all contain carbon. Limestone was formed by the calcium carbonate from sea organisms and their shells. Crude oil and natural gas form from the decomposition of living animals and plants.	Students should be able to describe and explain the formation of deposits of limestone, coal, crude oil and natural gas.
How does the atmosphere help the Earth maintain stable surface temperatures?	Greenhouse gases in the atmosphere maintain temperatures on Earth high enough to support life. Water vapour, carbon dioxide and methane are greenhouse gases.	Oreenhouse gases in the atmosphere maintain temperatures on Earth high enough to support life. Water vapour, carbon dioxide and methane are greenhouse gases.
What are the long and short term impacts of the greenhouse effect?	Short term effects: Average surface temperature of earth increases. Long term effect: Rising sea levels, more extreme weather patterns.	Students should be able to describe the greenhouse effect in terms of the interaction of short and long wavelength radiation with matter.
What types of human activities increase the amounts of greenhouse gases in the atmosphere?	Any human activity that produces carbon dioxide and methane.	Some human activities increase the amounts of greenhouse gases in the atmosphere. These include: - carbon dioxide - methane. Students should be able to recall two human activities that increase the amounts of each of the greenhouse gases carbon dioxide and methane.
What do most scientists believe will happen to the Earth?s atmosphere?	Many scientists believe that human activities will cause the temperature of the Earth?s atmosphere to increase at the surface and that this will result in global climate change.	Based on peer-reviewed evidence, many scientists believe that human activities will cause the temperature of the Earth's atmosphere to increase at the surface and that this will result in global climate change.
What difficulties can such complex systems as global climate change cause?	They lead to simplified models, speculation and opinions presented in the media that may be based on only parts of the evidence and which may be biased.	There are difficulties in such complex systems as global climate change. This leads to simplified models, speculation and opinions presented in the media that may be based on only parts of the evidence and which may be biased.
What is the importance of peer reviewing results and of communicating results to a wide range of audiences.	Peer reviewing is important within the science community as it prevents bias and allows links to be made within and outside certain specialisms as well as to educate wider audiances.	Students should be able to recognise the importance of peer review of results and of communicating results to a wide range of audiences.
What is a major cause of climate change?	An increase in average global temperature is a major cause of climate change.	An increase in average global temperature is a major cause of climate change. There are several potential effects of global climate changes.
Describe briefly four potential effects of global climate change	The potential effects of global climate change are rising sea levels, damage to ozone layer, increase earth temperature, polar ice caps melting, animals may become extinct, damage to coral reefs.	Students should be able to describe briefly four potential effects of global climate change
What are the scale, risk and environmental implications of global climate change.	Global scale with different affects in different regions. Risk to lost of home, crops, spread of disease, more extreme weather events such as hurricanes and flooding and species extinction.	Students should be able to discuss the scale, risk and environmental implications of global climate change.
What is a carbon footprint?	The carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.	The carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
How can a carbon footprint be reduced?	The carbon footprint can be reduced by reducing emissions of carbon dioxide and methane.	The carbon footprint can be reduced by reducing emissions of carbon dioxide and methane.
What actions are required to reduce emissions of carbon dioxide and methane?	The main way to reduce emissions of carbon dioxide in the air is to burn less fossil fuels. Unfortunately, we depend on the burning of fossil fuels for heating, electricity generation and transport. If we are to burn less fossil fuels, we will need alternatives for these essential activities. Cattle farming produces a vast quantity of methane and therefore an effective way to reduce the emissions of methane would be o move away from a meat based diet towards a more plant based diet. This would also be a more effective use of land as the land used to produce cattle feed could be used to grow crops and vegetables.	Students should be able to describe actions to reduce emissions of carbon dioxide and methane
What human activity is the biggest contributor to an increase in atmospheric pollutants?	The combustion of fossil fuels is a major source of atmospheric pollutants.	The combustion of fuels is a major source of atmospheric pollutants.
What do most fuels contain?	Most fuels, including coal, contain carbon and/or hydrogen and may also contain some sulfur.	Most fuels, including coal, contain carbon and/or hydrogen and may also contain some sulfur.
Name the gases commonly released into the atmosphere when a fuel is burned?	Carbon dioxide, water vapour, carbon monoxide, sulfur dioxide and oxides of nitrogen. Solid particles and unburned hydrocarbons may also be released that form particulates in the atmosphere.	The gases released into the atmosphere when a fuel is burned may include carbon dioxide, water vapour, carbon monoxide, sulfur dioxide and oxides of nitrogen. Solid particles and unburned hydrocarbons may also be released that form particulates in the atmosphere.
How does burning fuels produce carbon monoxide, soot (carbon particles), sulfur dioxide and oxides of nitrogen?	Carbon monoxide is produced through incomplete combustion due to limited oxygen. Soot is produced from carbon that has not reacted during combustion. Sulfur dioxide is produced due to sulfur in the fuel reacting with oxygen in hot enginges. Nirtogen oxides are formed from nitrogen in the air reacting with oxygen.	Students should be able to describe how carbon monoxide, soot (carbon particles), sulfur dioxide and oxides of nitrogen are produced by burning fuels.
What are the impacts of emissions of carbon monoxide?	Carbon monoxide is a toxic gas. It is colourless and odourless and so is not easily detected.	Carbon monoxide is a toxic gas. It is colourless and odourless and so is not easily detected.
What environmental impact does the emission of sulfur dioxide and oxides of nitrogen cause?	Sulfur dioxide and oxides of nitrogen cause respiratory problems in humans and cause acid rain.	Sulfur dioxide and oxides of nitrogen cause respiratory problems in humans and cause acid rain.
What environmental impact do particulates cause?	Particulates cause global dimming and health problems for humans.	Particulates cause global dimming and health problems for humans.
Describe and explain the problems caused by increased amounts of the following pollutants in the atmosphere: a) Carbon Dioxide b) Nitrogen Oxides c) Sulfur Dioxide d) Particulates	a) Greenhouse gas that contributes to global warming. b) Dissolves in water droplets in clouds, it makes the rain more acidic than normal. This is called acid rain. c) Same as b) d) Very small pieces of solids, mainly carbon, that are released into the air during incomplete combustion. Contribute towards global dimming (the reduction of sunlight that makes it to the earths surface).	Students should be able to describe and explain the problems caused by increased amounts of these pollutants in the air.
What do humans use the Earth's resources for?	Humans use the Earth's resources to provide warmth, shelter, food and transport.	Humans use the Earth's resources to provide warmth, shelter, food and transport.
What do natural resources provide?	Natural resources, supplemented by agriculture, provide food, timber, clothing and fuels.	Natural resources, supplemented by agriculture, provide food, timber, clothing and fuels.
What are finite resources used for?	Finite resources from the Earth, oceans and atmosphere are processed to provide energy and materials.	Finite resources from the Earth, oceans and atmosphere are processed to provide energy and materials.
What role has Chemistry played in improving agricultural and industrial processes?	Chemistry plays an important role in improving agricultural and industrial processes toprovide new products and in sustainable development, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.	Chemistry plays an important role in improving agricultural and industrial processes to provide new products and in sustainable development, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.
What are the names of natural products that are supplemented or replaced by agricultural and synthetic products?	The natural products that are supplemented/replaced by agricultural or synthetic products are nitrogen, phosphorus and potassium.	Students should be able to state examples of natural products that are supplemented or replaced by agricultural and synthetic products.
What is the difference between finite and renewable resources?	Finite resources are those which are limited. Renewable resources are those which can be replenished at the same rate that they are used up.	Students should be able to distinguish between finite and renewable resources given appropriate information.
What are orders of magnitude?	A system of classification determined by size, typically in powers of ten.	Students should be able to use orders of magnitude to evaluate the significance of data.
What different aspects of a products lifetime are assessed through a life cycle assessment?	Life cycle assessments (LCAs) are carried out to assess the environmental impact of products in each of these stages: - extracting and processing raw materials - manufacturing and packaging - use and operation during its lifetime - disposal at the end of its useful life, including transport and distribution at each stage.	Life cycle assessments (LCAs) are carried out to assess the environmental impact of products in each of these stages: - extracting and processing raw materials - manufacturing and packaging - use and operation during its lifetime - disposal at the end of its useful life, including transport and distribution at each stage.
Why are life cycle assessment not a purely objective process?	Life cycle assessments are not a purely objective process because allocating numerical values to pollutant effects is less straightforward and requires value judgments.	Use of water, resources, energy sources and production of some wastes can be fairly easily quantified. Allocating numerical values to pollutant effects is less straightforward and requires value judgements, so LCA is not a purely objective process.
Why is it important that life cycle assessments are completed by an unbiased impartial agency?	It is important that life cycle assessments are completed using an unbiased impartial agency to avoid misuse of data to reach pre-determined conclusions. e.g. to support a claim that a product is more environmentally friendly.	Selective or abbreviated LCAs can be devised to evaluate a product but these can be misused to reach pre-determined conclusions, eg in support of claims for advertising purposes.
What are the life cycle assessments that would be conducted for plastic and paper carrier bags?	The life cycle assessments that would be conducted for plastic and paper bags are the raw materials, manufacturing processing, which lasts longer, disposal, transport, emissions and waste.	Students should be able to carry out simple comparative LCAs for shopping bags made from plastic and paper.
What are the reasons behind the incentive Reduce, Reuse, Recycle?	Reduce, Reuse and Recycle is targeted to end users to reduce the use of limited resources, use of energy sources, waste and environmental impacts.	The reduction in use, reuse and recycling of materials by end users reduces the use of limited resources, use of energy sources, waste and environmental impacts.
Where are the raw materials found to produce products such as ceramics, metals and plastics?	The raw materials we use to make ceramics, metals and plastics are found within the earths crust.	Metals, glass, building materials, clay ceramics and most plastics are produced from limited raw materials.
Describe how the majority of energy is generated in order to process raw materials such as clay ceramics and metal ores?	Most energy used to process natural resources is generated from finite resources, such as fossil fuels.	Much of the energy for the processes comes from limited resources.
Evaluate the environmental impacts of quarrying in order to obtain natural resources	The Environmental impacts of quarrying can be: Once usage is complete, often old quarries can become u - Destruction of natural habitats - Pollutants released from use of chemicals and burning fossil fuels in operation of quarry - Permanently disfigure the local environment and are often visible from long distances	Obtaining raw materials from the Earth by quarrying and mining causes environmental impacts.
Give an example of a product that can be reused and a product that can be recycled.	Some products, such as glass bottles, can be reused. Glass bottles can be crushed and melted to make different glass products. Other products cannot be reused and so are recycled for a different use such as plastics and metals.	Some products, such as glass bottles, can be reused. Glass bottles can be crushed and melted to make different glass products. Other products cannot be reused and so are recycled for a different use.
How can metals be recycled?	Metals can be recycled by melting and recasting or reforming into different products.	Metals can be recycled by melting and recasting or reforming into different products.
What does the amount of separation for a product rely on? Give an example.	The amount of separation required for recycling depends on the material and the properties required of the final product. For example, some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.	The amount of separation required for recycling depends on the material and the properties required of the final product. For example, some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.
What ways can reducing the use of limited resources be achieved?	Reducing the use of limited resources be achieved by producing less waste, reusing certain products, recycling certain products.	Students should be able to evaluate ways of reducing the use of limited resources, given appropriate information.
What should the quality of drinking water be like?	The quality of drinking water should have low levels of dissolved salts and microbes.	Water of appropriate quality is essential for life. For humans, drinking water should have sufficiently low levels of dissolved salts and microbes.
What must be done to the waste water produced by urban lifestyles and industrial processes before it can be released back into the environment?	Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment.	Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment.
What is the name given to water that is safe to drink?	The name given to water that is safe to drink is potable water.	Water that is safe to drink is called potable water. Potable water is not pure water in the chemical sense because it contains dissolved substances.
What will be required to be removed from a) agricultural waste water and b)industrial waste water?	Agricultural waste water require removal of organic matter and harmful microbes. Industrial waste water may require removal of organic matter and harmful chemicals.	Sewage and agricultural waste water require removal of organic matter and harmful microbes. Industrial waste water may require removal of organic matter and harmful chemicals.
What factors decide which methods are used to produce potable water?	The methods used to produce potable water depend on available supplies of water and local conditions.	The methods used to produce potable water depend on available supplies of water and local conditions.
What does sewage treatment include?	Sewage treatment includes: - screening and grit removal - sedimentation to produce sewage sludge and effluent - anaerobic digestion of sewage sludge - aerobic biological treatment of effluent.	Sewage treatment includes: ? screening and grit removal ? sedimentation to produce sewage sludge and effluent ? anaerobic digestion of sewage sludge ? aerobic biological treatment of effluent.
What stages do most of the potable water in the UK produced?	The stages that most potable water is produced in the UK is: - choosing an appropriate source of fresh water - passing the water through filter beds - sterilising.	In the United Kingdom (UK), rain provides water with low levels of dissolved substances (fresh water) that collects in the ground and in lakes and rivers, and most potable water is produced by: - choosing an appropriate source of fresh water - passing the water through filter beds - sterilising.
How is potable water obtained from a) waste ground and b) salt water?	Potable water can be obtained from waste ground through the three main stages of sedimentation, filtration and sterilizing. Potable water can be obtained from salt water through desalination by distillation or reverse osmosis.	Students should be able to comment on the relative ease of obtaining potable water from waste, ground and salt water.
What are three types of sterilising agents used for potable water?	Sterilising agents used for potable water include chlorine, ozone or ultraviolet light.	Sterilising agents used for potable water include chlorine, ozone or ultraviolet light.
What process can be used to make salt water / sea water potable when fresh water is limited?	If supplies of fresh water are limited, desalination of salty water or sea water may be required.	If supplies of fresh water are limited, desalination of salty water or sea water may be required.
How is desalination completed? (give two methods)	Desalination can be done by distillation or by processes that use membranes such as reverse osmosis.	Desalination can be done by distillation or by processes that use membranes such as reverse osmosis.
What is the main drawback of desalination processes?	Desalination processes require large amounts of energy.	These processes require large amounts of energy.
What is the difference between potable and pure water?	Pure water only contains water particles with no other substances. Potable water is safe to drink but contains other soluble ions.	Students should be able to distinguish between potable water and pure water.
What is the differences in the way that ground water and salty water is treated?	Salty water is treated by distillation or by reverse osmosis. Ground water is treated by - passing the water through filter beds and then sterilising using chlorine, ozone or UV light.	Students should be able to describe the differences in treatment of ground water and salty water.
What are the reasons for each step of producing potable water from ground water?	Potable water is filtered to remove any fine particles in the water. It is then steralised to kill microbes.	Students should be able to give reasons for the steps used to produce potable water.
How can analysis of the purity of water be carried out?	It is possible to analyse the purity of water by the boiling point. The closer the boiling point is to that of pure water, the more pure it is.	Students should be able to carry out analysis and purification of water samples from different sources, including pH, dissolved solids and distillation.
What will happen to the Earth's supplies of metal ores if we continue to extract them at the rate we are now?	The Earth's resources of metal ores are limited. Eventually they will run out.	The Earth?s resources of metal ores are limited.
What are new ways of extracting copper from low-grade ores called?	Copper ores are becoming scarce and new ways of extracting copper from low-grade ores include phytomining, and bioleaching.	Copper ores are becoming scarce and new ways of extracting copper from low-grade ores include phytomining, and bioleaching.
What do these new methods of copper extraction avoid?	These methods avoid traditional mining methods of digging, moving and disposing of large amounts of rock.	These methods avoid traditional mining methods of digging, moving and disposing of large amounts of rock.
How is phytomining carried out?	Phytomining uses plants to absorb metal compounds. The plants are harvested and then burned to produce ash that contains metal compounds.	Phytomining uses plants to absorb metal compounds. The plants are harvested and then burned to produce ash that contains metal compounds.
How is bioleaching carried out?	Bioleaching uses bacteria to produce leachate solutions that contain metal compounds.	Bioleaching uses bacteria to produce leachate solutions that contain metal compounds.
How can copper compounds be processed to obtain the metal.	The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis.	The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis.
What uses do we have for the ammonia produced through the Haber process?	Ammonia can be used to manufacture ammonium salts (used in fertilisers) and nitric acid.	Ammonia can be used to manufacture ammonium salts and nitric acid.
Recall the names of the salts produced when phosphate rock is treated with: a) nitric acid b) sulfuric acid c) phosphoric acid	a) Calcium nitrate b) Single superphosphate (a mixture of calcium sulfate and calcium phosphate) c) Triple superphosphate (calcium phosphate)	Students should be able to recall the names of the salts produced when phosphate rock is treated with nitric acid, sulfuric acid and phosphoric acid
What process is used to extract rocks containing phosphate compounds from the earth?	Mining. - The phosphate containing rocks must be processed further prior to being used in fertilisers.	Potassium chloride, potassium sulfate and phosphate rock are obtained by mining, but phosphate rock cannot be used directly as a fertiliser
How can rocks containing phosphate compounds be treated, in order to make soluble salts that can be used as fertilisers?	Phosphate rock is treated with nitric acid or sulfuric acid to produce soluble salts that can be used as fertilisers.	Phosphate rock is treated with nitric acid or sulfuric acid to produce soluble salts that can be used as fertilisers.
NPK fertilisers all contain which 3 elements?	N = Nitrogen P = Phosphorus K = Potassium	Compounds of nitrogen, phosphorus and potassium are used as fertilisers to improve agricultural productivity. NPK fertilisers contain compounds of all three elements.
Can NPK fertilisers be made using a variety of raw materials and different reactions?	Yes, Industrial production of NPK fertilisers can be achieved using a variety of raw materials in several integrated processes	Industrial production of NPK fertilisers can be achieved using a variety of raw materials in several integrated processes
NPK fertilisers are formulations of various salts. What is a formulation?	Any mixture or substance prepared according to a particular formula. NPK fertilisers are formulations of various salts containing appropriate percentages of the elements (nitrogen, phosphorus and potassium).	NPK fertilisers are formulations of various salts containing appropriate percentages of the elements.
How can corrosion be described?	Corrosion is the destruction of materials by chemical reactions with substances in the environment.	Corrosion is the destruction of materials by chemical reactions with substances in the environment.
How can corrosion be prevented?	Corrosion can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating.	Corrosion can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating.
What practical could be carried out to investigate the conditions needed for corrosion (rusting)?	A practical where a metal object e.g. a nail is kept in different conditions for example: 1. Only in air 2. Only in water 3. In air and water This would show that both air and water are needed for rusting to occur.	Students should be able to describe experiments and interpret results to show that both air and water are necessary for rusting.
What conditions are needed for corrosion to occur?	Rusting is an example of corrosion. Both air and water are necessary for iron to rust.	Rusting is an example of corrosion. Both air and water are necessary for iron to rust.
What does sacrificial protection mean?	Some coatings are reactive and contain a more reactive metal to provide sacrificial protection, eg zinc is used to galvanise iron.	Some coatings are reactive and contain a more reactive metal to provide sacrificial protection, eg zinc is used to galvanise iron.
How is aluminium protected from further corrosion?	Aluminium has an oxide coating that protects the metal from further corrosion.	Aluminium has an oxide coating that protects the metal from further corrosion.
Would a more or less reactive metal be used in sacrificial protection? Give a reason for your answer.	A more reactive metal is used as this would prevent the less reactive metal from rusting and become weakened.	Students should be able to explain sacrificial protection in terms of relative reactivity.
Are most everyday metals pure or alloys?	Most metals in everyday use are alloys.	Most metals in everyday use are alloys.
What are the alloys bronze and brass made up of?	Bronze is an alloy of copper and tin. Brass is an alloy of copper and zinc.	Bronze is an alloy of copper and tin. Brass is an alloy of copper and zinc.
What is the percentage of gold in 24 carat and 18 carat gold used for jewellery?	The proportion of gold in the alloy is measured in carats. 24 carat being 100 % (pure gold), and 18 carat being 75 % gold.	Gold used as jewellery is usually an alloy with silver, copper and zinc. The proportion of gold in the alloy is measured in carats. 24 carat being 100 % (pure gold), and 18 carat being 75 % gold.
What elements are present in the alloy steel?	Steels are alloys of iron that contain specific amounts of carbon and other metals.	Steels are alloys of iron that contain specific amounts of carbon and other metals.
How are the physical properties of high carbon and low carbon steels different?	High carbon steel is strong but brittle. Low carbon steel is softer and more easily shaped.	High carbon steel is strong but brittle. Low carbon steel is softer and more easily shaped.
What are the benefits of stainless steels that contain chromium and nickel?	Steels containing chromium and nickel (stainless steels) are hard and resistant to corrosion.	Steels containing chromium and nickel (stainless steels) are hard and resistant to corrosion.
What are the uses of low density aluminium alloys?	The uses of low density alloys can be for building bike frames and aeroplanes.	Aluminium alloys are low density.
What are the uses of high density steels?	High density steels are used for building materials. Low density steels are used	Students should be able to recall a use of each of the alloys specified.
How is soda-glass made?	Soda glass is made by heating a mixture of sand, sodium carbonate and limestone.	Most of the glass we use is soda-lime glass, made by heating a mixture of sand, sodium carbonate and limestone.
How is borosilicate glass made and what is the advantage of it over soda-glass?	Borosilicate glass, made from sand and boron trioxide, melts at higher temperatures than soda-lime glass.	Borosilicate glass, made from sand and boron trioxide, melts at higher temperatures than soda-lime glass.
How are clay ceramics made?	Clay ceramics, including pottery and bricks, are made by shaping wet clay and then heating in a furnace.	Clay ceramics, including pottery and bricks, are made by shaping wet clay and then heating in a furnace.
What is a composite and how are they made?	Most composites are made of two materials, a matrix or binder surrounding and binding together fibres or fragments of the other material, which is called the	Most composites are made of two materials, a matrix or binder surrounding and binding together fibres or fragments of the other material, which is called the reinforcement.
What are three examples of composites?	Some examples of composites are: 1. carbon fibre 2. plywood 3. reinforced concrete 4. Ceramic	Students should be able to recall some examples of composites.
What is a polymer?	A polymer is a large chain of monomers covalently bonded.	Students should be able to, given appropriate information explain how the properties of materials are related to their uses and select appropriate materials.
What factors determine the type of polymers that are made?	The properties of polymers depend on what monomers they are made from and the conditions under which they are made. For example, low density (LD) and high density (HD) poly(ethene) are produced from ethene.	The properties of polymers depend on what monomers they are made from and the conditions under which they are made. For example, low density (LD) and high density (HD) poly(ethene) are produced from ethene.
What is the difference between thermo softening and thermosetting polymers?	Thermosoftening polymers melt when they are heated. Thermosetting polymers do not melt when they are heated.	Thermosoftening polymers melt when they are heated. Thermosetting polymers do not melt when they are heated.
How are high density and low density poly(ethene) are produced from ethene?	High and Low density poly(ethene) are made using different catalysts and different reaction conditions.	Students should be able to explain how low density and high density poly(ethene) are both produced from ethene.
How are the structures of thermosoftening and thermosetting polymers different?	Thermosoftening polymers are no cross chains or branches between the polymer chains so slide easily past each other, this makes them change shape when heated. Thermosetting polymers have many cross chains or branches so are able to hold their sh	Students should be able to explain the difference between thermosoftening and thermosetting polymers in terms of their structures.

Mod	Number of Questions
0S	10
1B	10
1C	10
1P	10
BI	5