Dunoon Grammar School

Dunoon Grammar School

Chemistry Department

S3 Chemistry

Unit 5 Homework

Hydrocarbons

Name: ______Class: ______

Teacher: ______

MARK / 14 HOMEWORK 1

1. What two elements are hydrocarbons composed of? (1)

2. What are the two products when a hydrocarbon is burned in a plentiful oxygen supply? (1)

3. What property of hydrocarbons allows them to be separated into fractions

using fractional distillation? (1)

4. Consider the following fractions obtained by fractional distillation of crude oil:

gasoline fuel oil kerosene fuel gas residue

(a)  Which fraction is used to make:

(i)  Aircraft fuel? (1)

(ii)  Petrol for cars? (1)

(iii)  Bitumen for roads? (1)

(b) Name the fraction which contains molecules with carbon atoms in the following ranges.

(i) C1 to C4 (ii) C5 to C6 (iii) C9 to C13

(iv) C18 to C25 (v) >C25 (2)

(c) (i) Which has the higher boiling point, gasoline or residue? (1)

(ii) Explain your answer. (1)

(d) (i) Which is more flammable, fuel gas or kerosene? (1)

(ii) Explain your answer (1)

(e) (i) Which is more viscous, fuel oil or kerosene? (1)

(ii) Explain your answer. (1)

MARK / 16 HOMEWORK 2

1. How many bonds does a carbon always form with other atoms? (1)

2. What is the name of the simplest family of hydrocarbons? (1)

3. What is the name of the alkane with:

(a)  four carbon atoms (1)

(b)  seven carbon atoms (1)

4. State the number of carbon atoms in a molecule of

(a) pentane (1)

(b) octane (1)

5. Name the following alkanes: (2)

(a) / / (b) /

6. Name the following alkanes:

(a) CH3CH2CH2CH2CH2CH3 (1)

(b) CH3CH2CH2CH2CH3 (1)

7. Name the following hydrocarbons, and draw their full structural formula

(a) C4H10

(b) C8H18

(c) C7H16 (6)

MARK / 16 HOMEWORK 3

1.  The molecular formula for the first four alkanes are as follows:

CH4 C2H6 C3H8 C4H10

(a)  What is the general formula for the alkanes? (1)

(b)  Use the general formula to work out the molecular formula for the alkanes which have:

(i) 16 carbon atoms in each molecule

(ii) 36 hydrogen atoms in each molecule (2)

2.  The alkanes and alkenes are both examples of Homologous Series of compounds.

What is meant by the term ‘Homologous Series’? (2)

3. For each of the following molecules: (a) propene

(b) methane

(c) ethane

(d) butene

(i) draw the full structural formula (4)

(ii) draw the shortened structural formula (4)

4. (a) Explain what is meant by a ‘saturated hydrocarbon’. (1)

(b) Consider the list of hydrocarbons:

butane, ethane, octene, methane, butene

Name the hydrocarbons which are

(i) saturated (ii) unsaturated (2)

MARK / 12 HOMEWORK 4

1. What is the structural difference between an alkane and an alkene? (1)

2. How many carbon atoms are in a molecule of

(a) ethene? (1)

(b)  hexene? (1)

3. State the molecular formula for each of the following hydrocarbons.

(a) octane

(b) hexane

(c) the saturated hydrocarbon with 12 carbon atoms per molecule

(d) the unsaturated hydrocarbon with 10 carbon atoms per molecule (4)

4. Name the following ALKENES

(a) CH2CH2

(b) CH3CH2CHCH2

(c) C3H6

5. Name the following ALKENES (2)

(a) / / (b) /

6. (a) What is the General Formula for the ALKENES? (1)

(b) What is the molecular formula of the alkene with 12 carbons? (1)

(c)  What is the molecular formula of the alkene with 38 hydrogens? (1)

MARK / 16 HOMEWORK 5

1. C2H4 + Br2 X

(a)  Draw the full structural formula for substance X? (1)

(b)  What name is given to this type of chemical reaction? (1)

(c) Name the product of the reaction of C2H4 with H2 (1)

2. An example of cracking is shown in the equation below

C8H18 C6H14

A B C

(a) Why is cracking an important process? (1)

(b) Name the hydrocarbons A and B (1)

(c) What is the formula and the name of C? (2)

(d) Describe an experiment which can be used to distinguish between A and C. Remember to include the result of the experiment. (1)

3. The following reaction took place during a cracking process

C5H12 C3H6 + Y

(a)  Name compound Y and give its full structural formula. (2)

(b)  Explain whether Y would decolourise bromine solution or not. (1)

4. The following reaction took place during a cracking process:

C15H32 C2H4 + C7H16 + X

(a)  Name compound X and give its full structural formula. (2)

(b)  Explain whether X would decolourise bromine solution or not. (1)

5.  The dienes are a homologous series of hydrocarbons which possess two carbon-to-carbon double bonds within each molecule. The first three members of the series have the following formulae:

C4H6 C5H8 C6H10

(a)  Give the formula of the next member of the series after C6H10 (1)

(b)  What is the general formula for this homologous series? (1)