IGCSEScienceEdexcelScience (Double Award) (Modular)Chemistry Unit 1Exam Questions4. Organic Chemistry: Part 1Introducing organic chemistry

Introducing organic chemistry (Edexcel IGCSE Science (Double Award) (Modular): Chemistry Unit 1): Exam Questions

Exam code: 4XSD1

1 hour13 questions
Easy
Medium
Hard
1
1 mark

The displayed formulae of an organic compound is shown below.

A displayed formula with two carbon atoms joined by a single bond. The left carbon carries a bromine above, a bromine below and a hydrogen to the left. The right carbon carries a hydrogen above, a hydrogen below and a hydrogen to the right.

What is the empirical formula of this compound?

  • CHBr

  • CH2Br

  • C2H4Br2

  • CH4Br

Choose your answer

2
1 mark

The structures of four organic compounds are shown.

Four structures labelled A to D. A shows two carbon atoms joined by a double bond, each carrying two hydrogens, with every bond drawn. B shows a central carbon with four CH~3~ groups written as groups around it, with lines to the groups but no bonds drawn inside them. C shows three carbon atoms in a chain with every bond and hydrogen drawn. D shows five carbon atoms in a chain with every bond and hydrogen drawn.

Which one does not show the displayed formula of the compound?

  • 4-1-q1-image-a
  • 4-1-q1-image-b
  • 4-1-q1-image-c
  • 4-1-q1-image-d

Choose your answer

3
1 mark

Which of the following is not a feature of a homologous series? 

  • Compounds have the same functional group 

  • Compounds have the same physical properties

  • Compounds have the same general formula 

  • Compounds have similar chemical properties 

Choose your answer

4a
4 marks

This question is about alkanes and alkenes.

Complete the boxes by giving the missing information about the alkene with the molecular formula C2H4.

 Molecular formula

C2H4 

 Name

 

 Empirical formula

 

 General formula

 

 Displayed formula

 

How did you do?

4b
3 marks

Alkenes are unsaturated hydrocarbons. 

State what is meant by the terms unsaturated and hydrocarbon.

How did you do?

4c
4 marks

Butene, C4H8, is a member of the same homologous series as C2H4. 

Use the words in the box to complete the sentences.

chemical

general

group

functional

molecular

period

physical

structural

Butene, C4H8, and C2H4 have the same .................... formula and .................... group. 

They will show similar .................... properties but there will be differences in their .................... properties, such as density and boiling point.

How did you do?

4d
1 mark

When the alkene butene reacts with bromine, the product is dibromobutane, C4H8Br2.

Give a word equation for this reaction.

[1]

How did you do?

4e
1 mark

When the alkene butene reacts with bromine, the product is dibromobutane, C4H8Br2.

What is the name of this type of reaction?

  • addition

  • decomposition

  • neutralisation

  • substitution

Choose your answer

5a
1 mark

The structures of six organic compounds are shown.

Six displayed formulae labelled A to F. A has four carbon atoms in a chain with a double bond between the second and third. B has two carbon atoms joined by a double bond, each carrying two hydrogens. C has a carbon carrying three hydrogens joined to a second carbon, which is double bonded to an oxygen and single bonded to an O-H group. D has two carbon atoms joined by a single bond, with an O-H group on the second carbon. E has three carbon atoms in a chain with a fourth carbon, carrying three hydrogens, bonded above the middle one. F has four carbon atoms in an unbranched chain.

Give the name of F.

How did you do?

5b
1 mark

Identify two compounds that are members of the same homologous series as those shown in a).

How did you do?

5c
2 marks

Compounds E and F in part a) are isomers of each other.  

State what is meant by the term isomers.

How did you do?

5d
2 marks

Explain why B in part a) is an unsaturated hydrocarbon.

How did you do?

1a
1 mark

Ethene (C2H4) can be converted into chloroethene (C2H3Cl) in a two-stage process.

The first stage is to convert ethene into 1,2-dichloroethane, C2H4Cl2  

Ethene is reacted with hydrogen chloride and oxygen. 

Complete the chemical equation for this reaction.

.......... C2H4 + .......... HCl + .......... O2 → .......... C2H4Cl2 + .......... H2O

How did you do?

1b
1 mark

In the second stage, 1,2-dichloroethane is converted into chloroethene. 

C2H4Cl2 → C2H3Cl + HCl 

This is a thermal decomposition reaction. 

State what is meant by the term thermal decomposition.

How did you do?

1c
3 marks

The diagram shows the displayed formula of chloroethene.

A displayed formula with two carbon atoms joined by a double bond. The left carbon carries a hydrogen above and a hydrogen below, and the right carbon carries a chlorine above and a hydrogen below.

i) State why chloroethene is described as an unsaturated compound.

[1]

ii) Describe a test to show that chloroethene is unsaturated.

[2]

How did you do?

1d
1 mark

Name the polymer formed from chloroethene.

How did you do?

2
1 mark

The structures of six organic compounds are shown.

Six displayed formulae labelled A to F. A is one carbon carrying three hydrogens and one bromine. B is two carbon atoms joined by a double bond, each carrying two hydrogens. C is a central carbon bonded to four CH~3~ groups. D is two carbon atoms in a chain, each carrying three hydrogens. E is three carbon atoms in a chain. F is five carbon atoms in an unbranched chain.

Which two compounds are isomers of one another?

  • B and D

  • A and C

  • C and F

  • C and E

Choose your answer

3
1 mark

Which of the following reactions is an example of an addition reaction?

  • CH4 + ½O2 → CO + 2H2O

  • C2H4 + Br2 → C2H4Br2

  • CH4 + 2O2 → CO2 + 2H2O

  • CH4 + Br2 → CH3Br + HBr

Choose your answer

4a
4 marks

The alcohols form a homologous series with the general formula CnH2n+1OH.

The first five members of the homologous series are given in the table below.

alcohol

formula

methanol

CH3OH

ethanol

CH3–CH2–OH

propan-1-ol

butan-1-ol

CH3–CH2–CH2–CH2–OH

pentan-1-ol

CH3–CH2–CH2–CH2–CH2–OH

i) Complete the table.

[1]

ii) Complete the equation for the reaction of butan-1-ol in excess oxygen.

C4H9OH + .......O2 → ..................... + .....................

[2]

iii) What is the name of the type of reaction occurring between butan-1-ol and oxygen?

[1]

How did you do?

4b
3 marks

State three characteristics of a homologous series other than the variation of physical properties down the series.

How did you do?

4c
3 marks

There are four isomers with the molecular formula C4H9OH that are alcohols.

These are the displayed formulae of the isomers.

Three displayed formulae, labelled beneath. Butan-1-ol has four carbon atoms in an unbranched chain with an OH group on the end carbon. 2-Methylpropan-1-ol has three carbon atoms in a chain with a CH~3~ group above the middle carbon and an OH group on the end carbon. 2-Methylpropan-2-ol has three carbon atoms in a chain with a CH~3~ group above the middle carbon and an OH group below that same middle carbon.

i) Explain why they are isomers.

[2]

ii) Draw the displayed formula of the fourth isomer.

[1]

How did you do?

4d
4 marks

An alcohol has this percentage composition by mass.

C = 60.0% H = 13.3% O = 26.7%

i) Show by calculation that the molecular formula of the alcohol could be C3H8O.

[3]

ii) Explain why the empirical formula is also the molecular formula of the alcohol.

[1]

How did you do?

1a
4 marks

The formulas for four organic compounds are given in the table below.

Write the names of each of the compounds.

Structure

Name

CH3CH2CH2CH2OH

 

CH3CH2CH2NH2

 

CH3COOCH2CH2CH3

 

CH3CH2CH2OH

 

How did you do?

1b
2 marks

CH3CH2CH2OH undergoes a combustion reaction in excess oxygen. Write a balanced symbol equation for this reaction. 

How did you do?

1c
2 marks

Compound A has an Mr of 102 and contains the same functional group as CH3CH2CH2OH. Calculate the percentage by mass of carbon in compound A.

(Ar: O = 16, C = 12, H = 1)

How did you do?

1d
1 mark

Draw the displayed formula of CH3CH2CH2NH2

How did you do?

2a
3 marks

Compound X is a hydrocarbon with an Mr of 70 that contains 85.7% by mass of carbon. When bromine water is added to compound X it remains orange. 

Calculate the empirical formula of compound X

How did you do?

2b
1 mark

Using the information in part a), determine the structure of compound X.

How did you do?

2c
1 mark

Compound X reacts with chlorine in the presence of ultra-violet light. Write the equation for this reaction.

How did you do?

3a
2 marks

There is a number of compounds with the molecular formula C4H8.

Explain how more than one compound can have the same molecular formula.

How did you do?

3b
2 marks

Draw the displayed formulae of two isomers with the formula C4H8 that belong to different homologous series.

isomer 1

 

 

 

 

 

isomer 2

 

 

 

 

 

How did you do?

3c
4 marks

i) Describe a chemical test to show that compounds with the molecular formula C4H8 belong to different homologous series.

[3]

ii) Explain how the results of the chemical test in part (i) proves that compounds with the molecular formula C4H8 belong to different homologous series.

[1]

How did you do?

3d
2 marks

Some organic compounds with the molecular formula C4H8 can be hydrated to form alcohols.

i) Give a chemical equation for this reaction.

[1]

ii) State the name of this type of reaction.

[1]

How did you do?

4a
2 marks

The diagram shows the formulae of some organic compounds.

Six boxes labelled A to F. A is written as CH~4~. B is written as CH~3~CH~2~CH~2~CH~3~. C is written as CH~2~=CH–CH~3~. D is drawn out in full, with a carbon carrying a hydrogen above, a hydrogen below, a hydrogen to the left and a bromine to the right. E is written as CH~3~–CH–CH~3~ with a CH~3~ below the middle carbon. F is drawn out in full, with three carbon atoms in a chain, the two end carbons each carrying three hydrogens and the middle carbon carrying two.

i) Explain which compound is not a hydrocarbon.

[1]

ii) Explain which compounds are shown as displayed formulae.

[1]

How did you do?

4b
2 marks

An example of the reaction of compound B with a halogen is shown.

C4H10 + Cl2 → C4H9Cl + compound G

i) State the condition needed for this reaction to occur

[1]

ii) Deduce the formula of compound G.

[1]

How did you do?

4c
4 marks

Compound D undergoes combustion to form a toxic colourless gas, a brown gas and one other product.

i) Give a chemical equation for this reaction.

[2]

ii) Explain how the toxic colourless gas affects the respiratory system.

[2]

How did you do?

4d
4 marks

Compound H belongs to the same homologous series as compound A.

The complete combustion of one mole of compound H burns is represented by the equation

compound H + x O2 → y CO2 + z H2O

The numbers x, y and z are used to balance the equation.

i) One mole of compound H burning completely in oxygen produces 308 g of carbon dioxide and 144 g of water.

Calculate the values of y and z.

[Mr of CO2 = 44, Mr of H2O = 18]

[2]

y = ..........

z = ..........

ii) Determine the molecular formula of the compound H and the value of x.

[2]

molecular formula = ..........

x = ..........

How did you do?