4th Sep '25

Schemes of Work

C1
- C1.5
  - Lesson 01 - Why are chemical equations always balanced? Lesson Plan Lesson Title
    - The law of conservation of mass states that no atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants.
      - Suggested Activity:
        Model the law of conservation using molecular model kits.
        Teacher Demo:
        Lead Nitrate and potassium Iodide.
        
        Perform on balance no change in mass.
        
        Write simple word equations.
        
        Write simple symbol equations.
        
        Balance symbol equations.
        
        GF: balance complex equations and add state symbols.
        Equipment Required:
        Teacher Demo:
        Lead Nitrate and potassium Iodide.
        balance
    - This means that chemical reactions can be represented by symbol equations which are balanced in terms of the numbers of atoms of each element involved on both sides of the equation.
    - Students should understand the use of the multipliers in equations in normal script before a formula and in subscript within a formula.
  - Lesson 02 - What does the relative formula mass tell us? Lesson Plan Lesson Title
    - The relative formula mass (Mr) of a compound is the sum of the relative atomic masses of the atoms in the numbers shown in the formula.
      - Suggested Activity:
        Review the definition of relative atomic mass.
        
        Recall how to find the relative atomic mass from the Periodic Table.
        
        Define the relative molecular mass.
        
        Extended writing: write instructions to another student how to calculate the relative formula mass.
        
        Model compounds with different sized and coloured lego bricks pre-marked with symbol and Ar of different elements. Sum the Ars marked on the bricks to obtain the Mr.
        Equipment Required:
        Conservation of mass Demo only! Lead Bromide, potassium iodide in conical flask.
        Accurate balance
    - In a balanced chemical equation, the sum of the relative formula masses of the reactants in the quantities shown equals the sum of the relative formula masses of the products in the quantities shown.
  - Lesson 03 - Why do some reactions appear to have a mass change? Lesson Plan Lesson Title
    - Some reactions may appear to involve a change in mass but this can usually be explained because a reactant or product is a gas and its mass has not been taken into account. For example: when a metal reacts with oxygen the mass of the oxide produced is greater than the mass of the metal or in thermal decompositions of metal carbonates carbon dioxide is produced and escapes into the atmosphere leaving the metal oxide as the only solid product.
      - Suggested Activity:
        Extended writing: use measurements of mass before and after an experiment to explain what has happened to the mass during the experiment and why it has happened.
        Equipment Required:
        Use magnesium ribbon to produce magnesium oxide. Measure the mass of the ribbon at the start of the experiment, burn the ribbon in a strong Bunsen flame (SAFETY required) and measure the mass of the ribbon at the end of the experiment.
        
        Use HCl acid in a conical flask with CaCO3. Measure the mass of the reaction on a top pan balance as the reaction proceeds over two minutes.
    - Students should be able to explain any observed changes in mass in non-enclosed systems during a chemical reaction given the balanced symbol equation for the reaction and explain these changes in terms of the particle model.
    - Whenever a measurement is made there is always some uncertainty about the result obtained.
    - Students should be able to represent the distribution of results and make estimations of uncertainty
    - Students should be able to use the range of a set of measurements about the mean as a measure of uncertainty.
  - Lesson 04 - What is a mole? Lesson Plan Lesson Title
    - Chemical amounts are measured in moles. The symbol for the unit mole is mol.
      - Suggested Activity:
        Define one mole in terms of Mr and Ar
        
        Calculate the number of moles in a substance using the relative formula mass.
        
        Extended writing: write instructions to another student how to calculate the number of moles using the relative formula mass
        Measure out and compare 1 mole of elements like iron, sulfur, magnesium, copper, aluminium and so on.
        
        Measure out and compare one mole of common compounds, water, sodium chloride, calcium carbonate and so on.
        YouTube:
        What is a mole?
        
        Avogadro’s number – The mole
        Equipment Required:
        Examples of 1 Mole samples, in tray in racking.
    - How the mass of one mole of a substance calculated.
    - One mole of a substance contains the same number of the stated particles, atoms, molecules or ions as one mole of any other substance.
    - The number of atoms, molecules or ions in a mole of a given substance is the Avogadro constant.
    - The value of the Avogadro constant is 6.02 x 1023 per mole.
    - Students should understand that the measurement of amounts in moles can apply to atoms, molecules, ions, electrons, formulae and equations, for example that in one mole of carbon (C) the number of atoms is the same as the number of molecules in one mole of carbon dioxide (CO2).
    - Students should be able to use the relative formula mass of a substance to calculate the number of moles in a given mass of that substance and vice versa.
  - Lesson 05 - What are solutions? Lesson Plan Lesson Title
    - Many chemical reactions take place in solutions. The concentration of a solution can be measured in mass per given volume of solution, eg grams per dm3 (g/dm3).
      - Suggested Activity:
        Extended writing: Write instructions to another student on how to calculate the concentration, or how to rearrange the equation to calculate number of moles
        Extended writing: Write instructions to another student on how to carry out a titration. Include reasons for using a burette instead
        Equipment Required:
        x
    - Students should be able to calculate the mass of solute in a given volume of solution of known concentration in terms of mass per given volume of solution
    - Students should be able to (HT only) explain how the mass of a solute and the volume of a solution is related to the concentration of the solution.
    - It is important for sustainable development and for economic reasons to use reactions with high atom economy.
  - Lesson 06 - How do you calculate reacting masses? Lesson Plan Lesson Title
    - The masses of reactants and products can be calculated from balanced symbol equations.
      - Suggested Activity:
        Balance chemical equations and use these to calculate the masses of substances present.
        
        Extended writing: write instructions to another student use balanced chemical equations to calculate the masses of substances present.
        
        YouTube:
        Calculating Masses in Reactions
        
        https://www.youtube.com/watch?v=6KRcO3e36ZU
    - Chemical equations can be interpreted in terms of moles. For example: Mg + 2HCI --> MgCI2 + H2 shows that one mole of magnesium reacts with two moles of hydrochloric acid to produce one mole of magnesium chloride and one mole of hydrogen gas.
    - Students should be able to calculate the masses of substances shown in a balanced symbol equation
    - Students should be able to calculate the masses of reactants and products from the balanced symbol equation and the mass of a given reactant or product.
    - The balancing numbers in a symbol equation can be calculated from the masses of reactants and products by converting the masses in grams to amounts in moles and converting the numbers of moles to simple whole number ratios.
    - Students should be able to balance an equation given the masses of reactants and products.
    - Students should be able to change the subject of a mathematical equation.
  - Lesson 07 - What is a limiting factor? Lesson Plan Lesson Title
    - In a chemical reaction involving two reactants, it is common to use an excess of one of the reactants to ensure that all of the other reactant is used.
      - Suggested Activity:
        Define the term limiting reactant.
        Link the limiting reactant to the number of moles.
        Link the limiting reactant to the masses in grams.
        
        Use a small strip of magnesium ribbon in 20 ml HCl acid. Identify which reactant is the limiting reactant and state the reason for this choice.
        Equipment Required:
        HCl - different strengths
        Magnesium Ribbon
        Conical flasks
        Balloons
    - The reactant that is completely used up is called the limiting reactant because it limits the amount of products.
    - Students should be able to explain the effect of a limiting quantity of a reactant on the amount of products it is possible to obtain in terms of amounts in moles or masses in grams.
  - Lesson 08 - What infomation does yield tell you? Lesson Plan Lesson Title
    - Even though no atoms are gained or lost in a chemical reaction, it is not always possible to obtain the calculated amount of a product because:
      ??? the reaction may not go to completion because it is reversible
      ??? some of the product may be lost when it is separated from the reaction mixture;
      ? some of the reactants may react in ways different to the expected reaction.
      - Suggested Activity:
        Describe how atoms are lost or gained in a chemical reaction.
        
        Explain why atoms can be lost or gained in a chemical reaction.
        
        Calculate the theoretical yield for simple examples.
        
        Extended writing: write instructions to another student how to calculate the theoretical yield giving explained examples.
        
        Use Lego as a model for chemical reactions demonstrating the loss of product and use the model as a simple introduction to yield calculations.
        
        The same can be applied to atom economy.
        Equipment Required:
        Lego
    - The amount of a product obtained is known as the yield.
    - When compared with the maximum theoretical amount as a percentage, it is called the percentage yield.
      % Yield = Mass of product actually made / Maximum theoretical mass of product ? 100
    - Students should be able to calculate the percentage yield of a product from the actual yield of a reaction
    - (HT only) calculate the theoretical mass of a product from a given mass of reactant and the balanced equation for the reaction.
  - Lesson 09 - What is atom economy? Lesson Plan Lesson Title
    - The atom economy (atom utilisation) is a measure of the amount of starting materials that end up as useful products.
      - Suggested Activity:
        Describe how atoms are lost or gained in a chemical reaction.
        
        Explain why atoms can be lost or gained in a chemical reaction.
        
        Calculate the theoretical yield for simple examples.
        
        Extended writing: write instructions to another student how to calculate the theoretical yield giving explained examples.
        
        Use Lego as a model for chemical reactions demonstrating the loss of product and use the model as a simple introduction to yield calculations.
        
        The same can be applied to atom economy.
        Equipment Required:
        Lego
        Molymods
    - The percentage atom economy of a reaction is calculated using the balanced equation for the reaction as follows: Relative formula mass of desired product from equation / Sum of relative formula masses of all reactants from equation ? 100
    - Students should be able to calculate the atom economy of a reaction to form a desired product from the balanced equation
    - (HT only) explain why a particular reaction pathway is chosen to
      produce a specified product given appropriate data such as atom
      economy (if not calculated), yield, rate, equilibrium position and
      usefulness of by-products.
  - Lesson 10 - How do you calculate the concentration of a solution? Lesson Plan Lesson Title
    - The concentration of a solution can be measured in mol/dm3.
      - Suggested Activity:
        Calculate the atom economy for simple examples.
        
        Extended writing: write instructions to another student how to calculate the atom economy giving explained examples.
        
        Identify a chemical reaction that has a high atom economy and research the positives to industry of producing a high yield of useful product.
        
        Identify a chemical reaction that has a low atom economy and research the negatives to industry of producing a low yield of useful product and ways the reactions has been improved to increase the yield of useful product.
        
        Atom Economy Video
        https://www.youtube.com/watch?v=Zuyk4hfbjSA
    - The amount in moles of solute or the mass in grams of solute in a given volume of solution can be calculated from its concentration in mol/dm3.
    - If the volumes of two solutions that react completely are known and the concentration of one solution is known, the concentration of the other solution can be calculated.
      - Suggested Activity:
        complete an acid-base titration to determine the concentration of an unknown solution:
        http://www.rsc.org/learn-chemistry/resource/res00000697/titrating-sodium-hydroxide-with-hydrochloric-acid?cmpid=CMP00005972
        Equipment Required:
        Burette (30 or 50 cm3) (Note 1)
        
        Conical flask (100 cm3)
        
        Beaker (100 cm3)
        
        Pipette (20 or 25 cm3) with pipette filler
        
        Stirring rod
        
        Small (filter) funnel (about 4 cm diameter)
        
        Burette stand and clamp (Note 2)
        
        White tile (optional) (Note 3)
        
        Bunsen burner
        
        Tripod
        
        Pipeclay triangle (Note 4)
        
        Evaporating basin (at least 50 cm3 capacity)
        
        Crystallising dish (Note 5)
        
        Microscope or hand lens suitable for examining crystals in the crystallising dish
    - Students should be able to explain how the concentration of a solution in mol/dm3 is related to the mass of the solute and the volume of the solution
    - Opportunities within titrations including to determine concentrations of strong acids and alkalis. (WS)
  - Lesson 11 - How do you calculate the volume of gas reactants and products? Lesson Plan Lesson Title
    - Equal amounts in moles of gases occupy the same volume under the same conditions of temperature and pressure.
      - Suggested Activity:
        Recall the equation:
        number of moles =
        mass/(relative formula mass)
        Use the equation:
        volume of gas at rtp = number of moles x molar gas volume (24 dm3)
        for simple examples.
        
        Extended writing: write instructions to another student on how to calculate the volume of a gas.
        
        Use balanced equations and known volume of reactant/product to calculate the volumes of gaseous reactants/ products.
        
        Molar volumes of gases https://www.youtube.com/watch?v=UCmYSIjOnUA
        
        How to calculate gas volumes
        https://www.youtube.com/watch?v=_CyIgvYNolE
    - The volume of one mole of any gas at room temperature and pressure (20oC and 1 atmosphere pressure) is 24 dm3.
    - The volumes of gaseous reactants and products can be calculated from the balanced equation for the reaction.
    - Students should be able to calculate the volume of a gas at room temperature and pressure from its mass and relative formula mass
    - Students should be able to calculate volumes of gaseous reactants and products from a balanced equation and a given volume of a gaseous reactant or product
    - Students should be able to change the subject of a mathematical equation.