OCR Chemistry A

Structural isomerism

Specification references

  • 4.1.1 e)
  • M 4.2

Learning outcomes

After completing the worksheet you should be able to:

  • understand what is meant by structural isomerism
  • use ideas about structural isomerism to identify and name isomers of alkanes, alcohols, aldehydes, ketones, carboxylic acids,and esters.

Questions

1Alkanes are a group of hydrocarbons which have the general formula CnH2n+2.

aWhat is the molecular formula of the alkanes which have 5 carbon atoms?(1 mark)

bIn Table 1, draw out the skeletal formula of all the structural isomers of the alkanes which have 5 carbon atoms. (3 marks)

cIn Table 1, name all the structural isomers of the alkanes which have 5 carbon atoms.(3 marks)

Table 1

Skeletal formula
Name

2Aldehydes and ketones are both carbonyl compounds and contain the functional group, CO.

In Table 2, draw the displayed formula and name both of the carbonyl compounds with the molecular formula C3H6O. (4 marks)

Table 2

Displayed formula
Name

3Carboxylic acid and esters are structural isomers of each other. There are 6 possible structural isomers with the formula C4H8O2;
2 of which are carboxylic acids and 4 of which are esters.

aIn Table 3, draw out the displayed formula and name both of the carboxylic acids which have the molecular formula C4H8O2. (4 marks)

Table 3

Displayed formula
Name

bIn Table 4, draw out the displayed formula of all of the esters which have themolecular formula C4H8O2. (4 marks)

Table 4

4Haloalkanes are compounds in which at least one of the hydrogen atoms has been replaced by a halogen in an alkane. You will study these more in Chapter 15: Haloalkanes.

aDraw out the displayed formula of haloalkanes with the following molecular formulae.

iC3H7Cl(2 marks)

iiC3H6Cl2(4 marks)

iiiC4H9Br(4 marks)

bName all of the structures that you drew in part a.

iC3H7Cl(2 marks)

iiC3H6Cl2(4 marks)

iiiC4H9Br(4 marks)

© Oxford University Press 2015

This resource sheet may have been changed from the original1