Thursday 4th September
TODAY WE ARE
LEARNING ABOUT
 What is cracking and why is it done?
TODAY'S
KEY WORDS ARE
  • Cr_ck_ng  
  • C_t_lyst  
  • _nd_stry  
  • P_lym_r  
    		•

    Memory Anchor:

    2C2H4 + C3H6 + C8H18 [Mislead1] => [Mislead2] => [Mislead3] => [Module] => C2.2.04 [Ordering] => 50 [Method] => [GoFurther] => [Quiz] => [Flag] => 0 [Code] => C2.2.04 [Title] => What is cracking and why is it done? ) [5] => Array ( [RowID] => 12481 [KS] => 4 [PosCode] => [SpecCode] => 4.7.1.4.e [Point] => Alkenes are more reactive than alkanes and react with bromine water, which is used as a test for alkenes. [SepOnly] => 0 [HTOnly] => 0 [KeyWord] => [MemoryAnchor] => [Activity] => Teach students that C=C bond in alkenes and that is what makes them different to alkanes [Equipment] => [Question] => Why do do alkenes react with bromine water, but alkanes don't? [Answer] => Alkenes react with bromine water because they have a C=C making them more reactive than alkanes (which don?t react with bromine water) [Mislead1] => [Mislead2] => [Mislead3] => [Module] => C2.2.04 [Ordering] => 60 [Method] => [GoFurther] => [Quiz] => [Flag] => 0 [Code] => C2.2.04 [Title] => What is cracking and why is it done? ) [6] => Array ( [RowID] => 12481 [KS] => 4 [PosCode] => [SpecCode] => 4.7.1.4.f [Point] => Students should be able to recall the colour change when bromine water reacts with an alkene. [SepOnly] => 0 [HTOnly] => 0 [KeyWord] => [MemoryAnchor] => [Activity] => Class practical - identifying unknown hydrocarbons using bromine water [Equipment] => test tubes filled with cyclohexane and cyclohexene labelled A and B. Bromine water. [Question] => What is the chemical test and positive result for identifying alkenes? [Answer] => The chemical test for identifying alkenes is to add bromine water, the positive result is that the bormine was decolourises. [Mislead1] => [Mislead2] => [Mislead3] => [Module] => C2.2.04 [Ordering] => 70 [Method] => [GoFurther] => [Quiz] => [Flag] => 0 [Code] => C2.2.04 [Title] => What is cracking and why is it done? ) [7] => Array ( [RowID] => 12481 [KS] => 4 [PosCode] => [SpecCode] => 4.7.1.4.g [Point] => There is a high demand for fuels with small molecules and so some of the products of cracking are useful as fuels. [SepOnly] => 0 [HTOnly] => 0 [KeyWord] => [MemoryAnchor] => [Activity] => Tidying away task: "Why is cracking so important?" Use images to prompt students if necessary [Equipment] => [Question] => Why is cracking of hydrocarbons so important? [Answer] => 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. [Mislead1] => [Mislead2] => [Mislead3] => [Module] => C2.2.04 [Ordering] => 90 [Method] => [GoFurther] => [Quiz] => [Flag] => 0 [Code] => C2.2.04 [Title] => What is cracking and why is it done? ) [8] => Array ( [RowID] => 12481 [KS] => 4 [PosCode] => [SpecCode] => 4.7.1.4.h [Point] => Alkenes are used to produce polymers and as starting materials for the production of many other chemicals. [SepOnly] => 0 [HTOnly] => 0 [KeyWord] => [MemoryAnchor] => [Activity] => [Equipment] => [Question] => How are alkenes used in chemical industry? [Answer] => Alkenes are used to produce polymers and as starting materials for the production of many other chemicals. [Mislead1] => [Mislead2] => [Mislead3] => [Module] => C2.2.04 [Ordering] => 90 [Method] => [GoFurther] => [Quiz] => [Flag] => 0 [Code] => C2.2.04 [Title] => What is cracking and why is it done? ) [9] => Array ( [RowID] => 12481 [KS] => 4 [PosCode] => [SpecCode] => 4.7.1.4.j [Point] => 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.) [SepOnly] => 0 [HTOnly] => 0 [KeyWord] => [MemoryAnchor] => [Activity] => [Equipment] => [Question] => How does modern life depend on the uses of hydrocarbons? [Answer] => Hydrocarbons are used to produce fuels for transport, generating electricity. They are the raw materials for producing plastics and other chemicals. [Mislead1] => [Mislead2] => [Mislead3] => [Module] => C2.2.04 [Ordering] => 100 [Method] => [GoFurther] => [Quiz] => [Flag] => 0 [Code] => C2.2.04 [Title] => What is cracking and why is it done? ) ) -->
    YOU WILL SHOW
    YOUR LEARNING BY...

    • Super Challenge:

      Stretch:

      Challenge:

    Key Questions:

    1. What is cracking?
      • Cracking is when hydrocarbons are broken down into smaller more useful molecules
    2. 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
    3. 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
    4. What are the products of cracking?
      • The products of cracking include alkanes and another type of hydrocarbon called alkenes.
    5. 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
    6. 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)
    7. 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.
    8. 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.
    9. How are alkenes used in chemical industry?
      • Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.
    10. 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.