4aOrganic Chemistry
Introduction — Edexcel Linear - OL (Chemistry) Revision Notes & Topical Questions
5 min read 7 parts Lesson 1 of 18 1 quiz
Lesson summary
Introduction Edexcel O Level Linear Chemistry notes: know that a hydrocarbon is a compound of hydrogen and carbon onlyChiral carbon has four different groups attached.Skeletal formulae show only bonds; C and H atoms implied.Boiling point rises with chain length; branching lowers …
- Introduction Edexcel O Level Linear Chemistry: what to do next
- Homologous series
- Functional group
- Structural isomers
- Stereoisomers
- Cis–trans isomerism
Part 1 of 6Key ideas
Key ideas
Chiral carbon has four different groups attached.
Skeletal formulae show only bonds; C and H atoms implied.
Boiling point rises with chain length; branching lowers it.
Part 2 of 6Syllabus points
1
know that a hydrocarbon is a compound of hydrogen and carbon only
2
understand how to represent organic molecules using empirical formulae, molecular formulae, general formulae, structural formulae and displayed formulae
3
know what is meant by the terms homologous series, functional group and isomerism
4
understand how to name compounds relevant to this specification using the rules of
5
understand how to write the possible structural and displayed formulae of an organic molecule given its molecular formula
6
understand how to classify reactions of organic compounds as substitution, addition and combustion knowledge of reaction mechanisms is not required
Part 3 of 6Process & sequence
Reaction types
Addition
Substitution
Elimination
Oxidation/reduction
Hydrolysis
Condensation
1
Homolytic fission
2
Free radicals
1
Heterolytic fission
2
Ions (nucleophile/electrophile)
Part 4 of 6Summary
Summary
Alkenes undergo electrophilic addition.
A chiral carbon has four different groups.
Part 5 of 6Keep going
Introduction Edexcel O Level Linear Chemistry: what to do next
These Introduction Edexcel O Level Linear Chemistry notes covered the key ideas, worked examples and exam technique for this topic. Check your Introduction Edexcel O Level Linear Chemistry understanding with the practice questions below, then reread any Introduction Edexcel O Level Linear Chemistry point you were unsure about before moving on.
2
Previous lesson: 3c Reversible reactions and equilibria — Notes
3
Next lesson: 4b Crude oil — Notes
5
Official syllabus: Pearson Edexcel International GCSEs
Part 6 of 6Compare: Compare
| Homologous series | Functional group | General formula | Suffix / prefix | Example | Key reaction |
|---|---|---|---|---|---|
| Alkanes | C–C, C–H | CₙH₂ₙ₊₂ | -ane | Propane | Free-radical substitution |
| Alkenes | C=C | CₙH₂ₙ | -ene | Propene | Electrophilic addition |
| Halogenoalkanes | C–X | CₙH₂ₙ₊₁X | halo- | Bromoethane | Nucleophilic substitution |
| Alcohols | –OH | CₙH₂ₙ₊₁OH | -ol | Ethanol | Oxidation, esterification |
| Aldehydes | –CHO | — | -al | Ethanal | Oxidised to acids |
| Ketones | C=O (internal) | — | -one | Propanone | Not oxidised easily |
| Carboxylic acids | –COOH | — | -oic acid | Ethanoic acid | Acid reactions, esters |
| Esters | –COO– | — | -yl -oate | Ethyl ethanoate | Hydrolysis |
Key terms
Command terms
Command terms
Give / State / Name
Recall a fact; one idea per mark.
Define
Give the exact meaning using the specification keywords.
Describe
Give an account of what happens / the pattern in data, quoting values; no reasons needed.
Explain
Give reasons with linked statements (cause → effect). Each linked step is usually a separate marking point.
Suggest
Use knowledge in a new context; more than one answer may be accepted.
Compare
Similarities and differences; each point must refer to both items.
Calculate
Show working; include units; check significant figures. Method marks are given even if the final answer is wrong.
Discuss
Explore the issue from different angles and link the points.
Evaluate / Assess
Weigh strengths and weaknesses and reach a supported judgement.
Deduce
Draw a conclusion from the information given.
Justify
Support a statement/choice with evidence.
Exam technique
Keywords the mark scheme looks for in this lesson
Keywords the mark scheme looks for in this lesson
Homologous series · Functional group · Structural isomers · Stereoisomers · Cis–trans isomerism · Optical isomers · Nucleophile · Electrophile
Learn each definition in the Key words tab exactly; a missing keyword in a definition usually loses the mark.
How to get full marks (examiner guidance)
How to get full marks (examiner guidance)
Use specification keywords exactly (e.g. electronegativity, nucleophile, dynamic equilibrium, activation energy).
Link ideas
Link ideas for “explain” each marking point is usually a cause → consequence step; unlinked facts often score nothing.
Use the information in the question
“discuss/evaluate” answers must use the data provided and match the number of marks.
Convert units carefully (mg → g, cm³ → dm³) and show working for calculations.
Avoid vague words
“it”, “stuff”, “things”, “goes up”, “energy is made”. Name the substance and the process.
Do not extrapolate a graph line beyond the data or to zero unless asked.
Six-mark extended responses are marked on content AND a logical, linked line of reasoning.
Marked practiceQuizzes for this lesson
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