Chemistry study notes
Organic Chemistry
Recognise molecular families and connect structures, reactions, fuels and materials.
SEC G2 Science K223 / K225 (2027)
Choose a topic
5 topicsFuels, fractions and bioethanol
Follow carbon from a resource to useful products.
Alkanes: build a valid carbon skeleton
Use four bonds per carbon and one per hydrogen.
Alkenes: a double bond creates new reactions
Distinguish substitution, addition and cracking.
Addition polymers: open the double bond, keep the substituents
A repeat unit shows the pattern within a long chain.
Evaluate plastic use and recycling
Compare what happens to the molecules and to the wider system.
Scope
Learning outcomes
8. Organic Chemistry (K223 / K225). Use the outcome map to find the explanation for a particular syllabus requirement.
See the learning outcome map
8.1(a) Identify non-renewable fuel sources
- Natural gas mainly methane
- Crude oil
8.1(b) Explain crude-oil fractionation
- Hydrocarbon mixture
- Fractions
- Competing fuel and chemical feedstock uses
8.1(c) Recognise renewable biofuel
- Bioethanol from sugarcane
8.1(d) Compare carbon impacts of fuels
- Plant-growth uptake offsets burning emissions
- Compare fossil-carbon release
- Sustainability depends on wider inputs
8.2(a) Describe homologous series
- General formula
- Similar chemistry
- Gradual melting/boiling/viscosity change with size/mass
Alkanes: build a valid carbon skeletonFuels, fractions and bioethanol
8.2(b) Describe alkanes
- Saturated hydrocarbons
- CnH2n+2
8.2(d) Describe alkane reactions
- Methane combustion
- Chlorine substitution with UV
- Generally unreactive otherwise
8.2(e) Describe alkenes
- Unsaturated hydrocarbons
- CnH2n
8.2(g) Explain cracking
- Alkenes and hydrogen products
- Demand for smaller refinery molecules
- Heating/catalyst conditions
Alkenes: a double bond creates new reactionsFuels, fractions and bioethanol
8.2(h) Distinguish saturation
- Molecular structure
- Aqueous bromine test
8.2(j) Explain polyunsaturated food molecules
- More than one C=C
8.2(k) Explain margarine manufacture
- Hydrogen addition to vegetable oils
- Solid product
- Nickel catalyst and heat
8.2(c) Draw and name alkanes
- Unbranched C1-C3
- Methane to propane
8.2(f) Draw and name alkenes
- Unbranched C2-C3
- Ethene and propene
8.2(i) Describe ethene reactions
- Combustion
- Polymerisation
- Bromine and hydrogen addition
- Essential conditions
Alkenes: a double bond creates new reactionsAddition polymers: open the double bond, keep the substituents
8.3(a) Describe polymers and monomers
- Large molecules from small units
- Different monomers give different polymers
Addition polymers: open the double bond, keep the substituents
8.3(b) Explain poly(ethene) formation
- Addition polymerisation of ethene
Addition polymers: open the double bond, keep the substituents
8.3(c) Identify poly(ethene) uses
- Plastic bags
- Clingfilm
Addition polymers: open the double bond, keep the substituents
8.3(d) Deduce addition-polymer structures
- Monomer to repeat unit
- Repeat unit to monomer
Addition polymers: open the double bond, keep the substituents
8.3(e) Explain plastic pollution
- Non-biodegradability
- Disposal impacts
8.3(f) Compare recycling routes
- Physical: poly(ethene) melted into pellets
- Chemical: cracking into fuel
8.3(g) Evaluate recycling issues
- Social
- Economic
- Environmental