AQA GCSE Chemistry - 7.1 Hydrocarbons: Fuel & Feedstock - Organic chemistry fundamentals

Sep 5, 2026

Revision notes for AQA GCSE Chemistry section 7.1 Hydrocarbons: Fuel & Feedstock, focusing on organic chemistry and hydrocarbons. Covers the definition of organic chemistry, carbon bonding and functional groups, classification by dominant functional group, and homologous series ideas such as shared functional group, general formula, incremental -CH2- changes, and trends in physical properties like boiling point, melting point, and density. Includes explanations of formula types (general, displayed, molecular, structural), crude oil composition and formation, and examiner guidance plus example data for alkanes.

LanguageEnglish

CategoryExam

FormatPDF

Pages20

Reading Time50 min

AccessFree to download

7.1 Hydrocarbons: Fuel & Feedstock

Crude Oil, Hydrocarbons & Alkanes

What is organic chemistry?

Types of formulae

What is a homologous series?

Composition of crude oil

Alkanes

Head to www.savemyexams. com for more awesome resources AQA GCSE Chemistry: Combined Science 7.1 Hydrocarbons: Fuel & Feedstock Contents Crude Oil, Hydrocarbons & Alkanes Fractional Distillation & Petrochemicals Properties of Hydrocarbons Cracking & Alkenes Page 1 of 20 © 2015 − 2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers Your notes Head to www.savemyexams. com for more awesome resources Crude Oil, Hydrocarbons & Alkanes What is organic chemistry? Organic chemistry is the chemistry of carbon compounds Carbon forms avast number of compounds because it can form strong covalent bonds with itself This enables it to form long chains of carbon atoms, and hence an almost infinite variety of carbon compounds are known Carbon always forms four covalent bonds which can be single, double or triple bonds A functional group is a specific atom or group of atoms which confer certain physical and chemical properties onto the molecule Organic molecules are classified by the dominant functional group on the molecule Organic compounds with the same functional group, but a different number of carbon atoms, are said to belong to the same homologous series Everytime a carbon atom is added to the chain, two hydrogen atoms are also added Organic compounds can be represented ina number of ways Types of Formulae General Formulae This type of formula tells you the composition of any member of a whole homologous series of organic compound For example, all of the alkanes have the general formula CnH2n+2 This tells you that however many carbon atoms there are in the alkane, doubling this number and adding two will give you the number of hydrogen atoms present in the alkane Displayed Formulae This shows the spatial arrangement of all the atoms and bonds in a molecule Molecular Formulae This shows the actual number of each atom in a molecule, one molecule at a time Displayed and molecular formulae Page 2 of 20 © 2015 − 2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers Your notes Head to www.savemyexams. com for more awesome resources The displayed formulae and molecular formulae of butane and butene Structural Formulae This gives enough information to make the structure clear, but most of the actual covalent bonds are omitted Only important bonds are shown, such as double and triple bonds Identical groups can be bracketed together Example of a structural formula Page 3 of 20 © 2015 − 2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers Your notes Head to www.savemyexams. com for more awesome resources Representing structural formulae of pentane and two alkenes What isa homologous series? Things we can say about a homologous series: each member has the same functional group each member has the same general formula each member has similar chemical properties each subsequent member differs by-CH2- members have gradually changing physical properties, for example, boiling point, melting point and density As a homologous series is ascended, the size of the molecule increases This has an effect on the physical properties, such as boiling point and density Homologous Series of Alkanes Table | Name of alkane | Number of carbons | Chemical formula | Melting point / oC | State at room temperature | Boiling point / oC | | --- | --- | --- | --- | --- | --- | | Methane | 1 | CH4 | –182 | gas | –162 | | Ethane | 2 | C2 H6 | –183 | gas | –89 | | Propane | 3 | C3 H8 | –188 | gas | –42 | | Butane | 4 | C4 H10 | –138 | gas | –1 | Page 4 of 20 © 2015 − 2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers Your notes Head to www.savemyexams. com for more awesome resources Composition of crude oil Crude oil is a finite resource which we find in the Earth 's crust Crude oil is a complex mixture of lots of different hydrocarbon compounds of differ

FAQs

How do functional groups and homologous series relate in organic chemistry?

A functional group is a specific atom or group that gives molecules particular physical and chemical properties. Organic molecules are classified by the dominant functional group, and compounds with the same functional group and different carbon counts belong to the same homologous series.

What are the different types of formulae and what does each show?

General formulae show the composition pattern for members of a homologous series. Displayed formulae show atoms and bonds spatially. Molecular formulae show the actual number of each atom in one molecule. Structural formulae show enough information to make the structure clear, with most bonds omitted except important ones such as double or triple bonds.

What properties and trends are expected when moving up a homologous series of alkanes?

Members of a homologous series share the same functional group, general formula, and similar chemical properties, and each successive member differs by -CH2-. As the series is ascended, molecule size increases, affecting physical properties such as boiling point, melting point, and density.

Sep 5, 2026

Upload by Lucas Martin