New
New
Year 10
AQA
Higher

Hydrocarbons

I can describe alkanes and represent the first four by name, molecular formulae and displayed formulae.

New
New
Year 10
AQA
Higher

Hydrocarbons

I can describe alkanes and represent the first four by name, molecular formulae and displayed formulae.

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Lesson details

Key learning points

  1. Hydrocarbons are simple covalent compounds made of hydrogen and carbon atoms only.
  2. Hydrocarbons are found in crude oil, and are used as fuels and feedstock.
  3. Alkanes consist of chains, or rings, of carbon atoms that are each also bonded to hydrogen atoms.
  4. Alkanes are a homologous series of hydrocarbons, with the same general formula with a trend in properties.
  5. The general formula for an alkane is CnH2n+2.

Common misconception

Students often think that the prefix hydro- in the term hydrocarbons means they contain water; also that hydrocarbons and crude oil are synonymous.

Use diagrams to show hydrocarbon composition and compare crude oil to pure hydrocarbons, highlighting the difference visually.

Keywords

  • Hydrocarbon - Simple covalent compounds made of carbon and hydrogen atoms only.

  • Feedstock - Raw materials used in chemical processes to produce other substances.

  • Alkane - Saturated hydrocarbons (have only single bonds between carbon and hydrogen atoms).

  • Homologous series - Compounds that have the same general formula, with neighbouring molecules often differing by CH₂, showing similar chemical properties and physical property trends.

  • Nomenclature - A collection of rules for naming things (in chemistry it refers to the naming of chemical substances).

Incorporate real-world examples and experiments that show the broad use of hydrocarbons in everyday products, fostering a deeper understanding of organic chemistry's impact on technology and daily life.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Which of the following is a characteristic of molecular compounds?
Composed of metal atoms
Made from metal and non-metal atoms
Correct answer: Formed from non-metal atoms
Q2.
In distillation, what characteristic is primarily used to separate substances in a mixture?
Density
Correct answer: Boiling point
Molecular weight
Colour
Q3.
Carbon will form a maximum of bonds to other atoms.
Correct Answer: 4, four
Q4.
When oxygen atoms bond together to make diatomic oxygen molecules (O₂), this is known as a double covalent bond.
Correct answer: True
False
Q5.
Which property increases as the strength of intermolecular forces increases?
Electrical conductivity
Malleability
Correct answer: Boiling point
Solubility in water
Q6.
Select all the true statements about simple molecular substances.
Correct answer: Low melting points
Correct answer: Cannot conduct electricity
High melting points
Conduct electricity only when molten or dissolved
Conduct electricity all the time

6 Questions

Q1.
Which elements make up hydrocarbons?
Correct answer: carbon
Correct answer: hydrogen
oxygen
nitrogen
Q2.
Which of the following are correct statements about compounds in the same homologous series?
Correct answer: have the same general formula
Correct answer: have similar chemical properties
Correct answer: show a trend in physical properties
neighbours in the series differ by -CH₃ group
are always chain structures
Q3.
Saturated hydrocarbons are called . They are saturated as they only contain single bonds between the carbon atoms.
Correct Answer: alkane, alkanes
Q4.
Which of the following is not a use of hydrocarbons?
fuel
solvent
feedstock
detergent
Correct answer: food
Q5.
Which of the following is the correct general formula for alkanes?
Correct answer: CnH2n+2
CnH2n
C2nHn+2
C2n+2H2n
CnHn
Q6.
Order the following hydrocarbons by carbon chain length. Start with the shortest carbon chain.
1 - methane
2 - ethane
3 - propane
4 - butane