Year 11 - Science
Cracking fractions of crude oil
Using Earth's resources
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit covers crude oil, its role as a hydrocarbon source, and separation by fractional distillation. It explores cracking, metal reactivity, and extraction methods, including biological alternatives. Emphasis is on recycling, life-cycle assessments, and evaluating decisions.
Lesson Summary
You will learn to describe the uses of different fractions of crude oil and describe what cracking is and how it is used to produce lighter fractions that are in greater demand.
Key Notes
- Fractions of crude oil have different properties and uses, affecting the demand for these molecules.
- Larger hydrocarbons can be broken down (cracked) to produce smaller, more useful molecules.
- Cracking can be done by various methods including catalytic cracking and steam cracking.
- The products of cracking include alkanes and alkenes, which have a double bond between two carbon atoms.
- Bromine water changes from orange/brown to colourless in the presence of an alkene.
Vocabulary To Learn
- cracking: Cracking is a thermal decomposition reaction where larger alkanes are broken down into smaller alkanes and alkenes.
- thermal decomposition: A thermal decomposition reaction is a type of reaction that uses heat to break down a reactant compound into two or more products.
- catalyst: A catalyst is a chemical that speeds up the rate of a reaction without itself being used up.
- saturated: Alkanes are saturated hydrocarbons as they contain only single bonds between carbon atoms.
- unsaturated: Unsaturated compounds contain at least one carbon-carbon double covalent bond.
Common Mistakes To Avoid
- Cracking is the same as fractional distillation.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Fractions of crude oil have different properties and uses, affecting the demand for these molecules. Larger hydrocarbons can be broken down (cracked) to produce smaller, more useful molecules.
2. Define this scientific word and use it in context. 'cracking'
Cracking is a thermal decomposition reaction where larger alkanes are broken down into smaller alkanes and alkenes. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Cracking is the same as fractional distillation. Correction: Fractional distillation separates hydrocarbons based on their boiling points. Cracking alters the molecular formula of compounds.
More Lessons In This Unit
- Alternative methods of extracting metals: phytoextraction and bioleaching Study Guide
- Alternative methods of extracting metals: phytomining and bioleaching Study Guide
- Developing a reactivity series for metals Study Guide
- Earth's resources and sustainable development Study Guide
- Extraction of metals by reduction Study Guide
- Fractional distillation of crude oil Study Guide
- Life cycle assessments (LCAs) Study Guide
- Polymer structures Study Guide
- Redox reactions Study Guide
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