Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
71–80 of 317 · Easy
Question 71
5 marks · Easy
Answer and see the solution →The molecule pentane belongs to a homologous series of organic compounds.
(a)[1 mark]State what is meant by a 'homologous series' in organic chemistry.
(b)[1 mark]Give the general formula for the homologous series that pentane belongs to.
(c)[1 mark]Write the molecular formula for pentane.
(d)[2 marks]Draw the displayed formula for pentane.
Question 72
5 marks · Easy
Answer and see the solution →Ethanol and ethene are two different organic compounds.
(a)[1 mark]Name the type of formula shown here for ethanol: CH3CH2OH
(b)[2 marks]Which functional group is present in ethanol and how does it affect its chemical properties?
(c)[2 marks]Write the displayed formula for ethene.
Question 73
5 marks · Easy
Answer and see the solution →A hydrocarbon in the alkane series contains 7 carbon atoms.
(a)[1 mark]Write the general formula for alkanes.
(b)[2 marks]Calculate the molecular formula for this alkane, showing your working.
(c)[2 marks]Draw the structural (condensed) formula for this alkane.
Question 74
5 marks · Easy
Answer and see the solution →Butanoic acid and butanol are both organic molecules with different functional groups.
(a)[1 mark]State the functional group present in butanoic acid.
(b)[1 mark]What type of formula is shown by this representation: CH3CH2CH2COOH?
(c)[2 marks]Explain how the functional group in butanol affects its chemical properties.
(d)[1 mark]Give one similarity and one difference between the general formulae of carboxylic acids and alcohols.
Question 75
1 mark · Easy
Answer and see the solution →State how long it takes for crude oil to form from the remains of sea plants and animals.
Question 76
3 marks · Easy
Answer and see the solution →Crude oil is an important natural resource. Answer all parts.
(a)[1 mark]State what crude oil is a mixture of.
(b)[1 mark]Give the names of the two elements found in all hydrocarbons in crude oil.
(c)[1 mark]Hydrocarbon molecules in crude oil have different sizes. Name one way in which large hydrocarbon molecules differ from small ones.
Question 77
2 marks · Easy
Answer and see the solution →Describe the process by which the soft parts of plants and animals in the sea are gradually converted into crude oil over time.
Question 78
3 marks · Easy
Answer and see the solution →The table shows four hydrocarbons found in crude oil. Use the data to answer the questions.
Physical properties of hydrocarbons in crude oil Hydrocarbon Number of carbon atoms Boiling point (°C) A 5 36 B 10 174 C 15 269 D 20 343 (a)[1 mark]Which hydrocarbon in the table has the highest boiling point?
(b)[1 mark]Describe the trend shown between the number of carbon atoms and boiling point.
(c)[1 mark]Predict the boiling point for a hydrocarbon with 12 carbon atoms, using the trend shown.
Question 79
1 mark · Easy
Answer and see the solution →Name one environmental problem caused by burning hydrocarbons from crude oil.
Question 80
3 marks · Easy
Answer and see the solution →Crude oil is formed over an extremely long period of time. Answer all parts.
(a)[1 mark]What happens to the remains of sea plants and animals after they die?
(b)[2 marks]State two conditions required for these remains to change into crude oil.