Unit 3The Chemical

Industry

1. The following diagram outlines the manufacture of sodium carbonate by the

Solvay Process.

(a) Name the reactants in the reaction taking place in the Solvay Tower.

(b) In reaction vessel A, carbon dioxide is produced by the following reactions.

CaCO3(s) CaO(s) + CO2(g) H = ………

C(s) + O3 (g) CO3 (g) H = ……….

For each reaction, add a sign after the H to show whether the reaction is

endothermic or exothermic.

(c) As well as ammonia, a salt and water are produced in reaction vessel B.

Write a balanced equation for the production of ammonia in this reaction vessel.

(a) Seawater, ammonia and

carbon dioxide.

(b) See opposite

(c)

NH4Cl + Ca(OH) 2

NH3 + CaCl2 + H2O

+ve

-ve

(d) The seawater used in the Solvay Process can contain magnesium ions.

These can be removed by addition of sodium carbonate solution.

Why is sodium carbonate solution suitable for removing contaminant

magnesium ions?

(e) Using the information in the flow diagram, give two different features of

the Solvay Process that make it economical.

(d) The magnesium ions react

with the carbonate ions to

form a precipitate of

magnesium carbonate which

can be filtered off.

(b) Seawater is cheap raw

material.

Ammonium chloride is

recycled in the plant.

2.

3 . Sphalerite is an impure zinc sulphide ore, containing traces of other metal compounds.

The flow diagram for the extraction of zinc from this ore is shown below

(a) Name gas A

(b) Name the type of reaction taking place in reaction vessel B.

(c) It is economical to make use of the sulphuric acid produced.

Add an arrow to the flow diagram to show how the sulphuric acid

could be used in this extraction.

(a) Sulphur dioxide.

(b) Displacement OR redox.

(c) See diagram.