5.4 Crude oil: Why is it still an essential resource?
Relate hydrocarbon structure to fractions, cracking, polymers, combustion and reaction energy.
How to study WJEC GCSE The Sciences
Move from a scientific model to a prediction or method, collect or interpret evidence, show quantitative working and finish with a conclusion whose limits match the data.
Core concepts
Concept 1
Explain fractional distillation and cracking using properties and demand.
Exam cue: Identify the unit, entered tier, supplied reference material, command word and relevant scientific enquiry skill.
Concept 2
Represent alkanes, alkenes, addition and polymerisation reactions.
Exam cue: Identify the hydrocarbon family from bonding or formula before drawing products or evaluating a resource choice.
Concept 3
Compare fuels and use energy-profile evidence for exothermic or endothermic change.
Exam cue: Use scientific terminology, show quantitative working with units, and connect conclusions to data and the stated model.
Concept 4
Official subtopics: 5.4.1 Crude oil and its products; 5.4.2 Alkanes and alkenes; 5.4.3 The production and uses of plastics; 5.4.4 Fuels and combustion; 5.4.5 Energy changes during a chemical reaction.
Concept 5
Scientific enquiry and mathematical skills apply in this topic; bold amplification is Higher Tier only.
Risk pitfalls and guardrails
Confusing cracking with fractional distillation or treating polymers as simple mixtures of monomers.
Guardrail: Do not import outgoing 3430QD content, another science route, a fixed required-practical list or unsupported tier and connection assumptions.
Recalling a fact without applying it to the observation, data, practical method or unfamiliar context.
Guardrail: Use the live secure pack: Task A may use groups of up to three; Task B is individual and highly controlled. Two enquiries are selected by the centre from three.
Importing content, required practicals, tier rules or paper structure from the outgoing WJEC or another awarding-body route.
Guardrail: Bold amplification is Higher-only. Units 1-6 may mix tiers, but Unit 7 is untiered.
Memory anchors
Hydrocarbon
A compound containing carbon and hydrogen only.
Alkane
A saturated hydrocarbon with only carbon-carbon single bonds.
Alkene
An unsaturated hydrocarbon containing a carbon-carbon double bond.
Cracking
Breaking large hydrocarbons into smaller, more useful molecules.
Polymer
A long-chain molecule made from repeating monomer units.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
What is a hydrocarbon? Link fraction properties, hydrocarbon structure and energy evidence to the stated use. Keep observations separate from scientific inferences.
Why is crude oil described as a finite resource? Link fraction properties, hydrocarbon structure and energy evidence to the stated use. Choose the option that remains valid across the stated range.
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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