Alkanes as Fuel
Alkanes are widely used as fuels because combustion is exothermic and releases useful energy. These pages separate the fuel topic into combustion chemistry, pollutant formation and catalytic converter treatment so students can connect equations, reaction conditions and environmental consequences.
Revision Notes
4 revision notes, in the order the specification teaches them.
Combustion
Revise complete and incomplete combustion of alkanes, including the key products, equations and why combustion releases energy.
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Oxides of Sulfur
Learn how sulfur impurities in fuels form sulfur dioxide and how sulfur oxides contribute to acid rain and environmental damage.
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Oxides of Nitrogen
Review how high temperatures in engines allow nitrogen and oxygen from air to react, producing nitrogen oxides that cause pollution.
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Catalytic Converter
Revise how catalytic converters use transition metal catalysts to convert harmful exhaust gases into less harmful products.
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Download, print and revise the reactions of this topic at a glance.
Summary maps
Download, print and revise the reactions of this topic at a glance.
Alkanes Map
OCR A Level Chemistry A · 4.1.2 Alkanes
Every reaction on one A4 page: reagents, conditions and reaction type for each arrow, colour coded, with the key tests.
Alkanes Summary Map
OCR A Level Chemistry A · 4.1.2 Alkanes
The whole section on one A4 page: σ-bonds and free rotation, the tetrahedral carbon, boiling points, low reactivity, combustion and carbon monoxide, with radical substitution and its limits in a table.
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Revision Game
Match reagents to products, free, with your board's reagents and conditions.
Study Cards
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Specification
Every specification point in this topic, in the exam board's own words. Rate how confident you are with each one.
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4.1.2
- a i
alkanes as saturated hydrocarbons containing single C–C and C–H bonds as σ-bonds (overlap of orbitals directly between the bonding atoms)
Revise - b i
explanation of the tetrahedral shape around each carbon atom in alkanes in terms of electron pair repulsion (see also 2.2.2 g–h)
Revise - b ii
explanation of the bond angle around each carbon atom in alkanes in terms of electron pair repulsion (see also 2.2.2 g–h)
Revise - c i
explanation of the variations in boiling points of alkanes with different carbon-chain length, in terms of induced dipole–dipole interactions (London forces) (see also 2.2.2 k)
Revise - c ii
explanation of the variations in boiling points of alkanes with different branching, in terms of induced dipole–dipole interactions (London forces) (see also 2.2.2 k)
Revise - d i
the low reactivity of alkanes with many reagents in terms of the high bond enthalpy of the σ-bonds present (see also 2.2.2 j)
Revise - d ii
the low reactivity of alkanes with many reagents in terms of the very low polarity of the σ-bonds present (see also 2.2.2 j)
Revise - f i
the reaction of alkanes with chlorine and bromine by radical substitution using ultraviolet radiation
Revise - f ii
the mechanism of radical substitution involving homolytic fission and radical reactions in terms of initiation (see also 4.1.1 f–g)
Revise - f iii
the mechanism of radical substitution involving homolytic fission and radical reactions in terms of propagation (see also 4.1.1 f–g)
Revise - f iv
the mechanism of radical substitution involving homolytic fission and radical reactions in terms of termination (see also 4.1.1 f–g)
Revise - g i
the limitations of radical substitution in synthesis by the formation of a mixture of organic products, in terms of further substitution
Revise - g ii
the limitations of radical substitution in synthesis by the formation of a mixture of organic products, in terms of reactions at different positions in a carbon chain
Revise
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