Chemistry Past Questions and Answers

Copper (ll) tetraoxosulphate (VI) is often added to swimming pools because it

A Prevents the growth of algae
B Coagulates suspended particles
C Neutralizes dissolved gases in water
D Reacts with any excess chlorine present
E Increases the amount of dissolved oxygen

Question 372:

The following salts dissolve readily in cold water except

A CaCI₂
B PbSO₄
C (NH₄)₂SO₄
D Na₂CO₃
E Na₂SO₃

Question 373:

What is the amount (in mole) of hydrogen gas that would be produced if 0.6 mole of hydrochloric acid reacted with excess zinc according to the following equation? Zn_(s) + 2HCI_(aq) â†’ ZnCI_2(aq) + H_2(g)

A 0.1 mole
B 0.2mole
C 0.3 mole
D 1.0 mole
E 2.9 moles

Question 374:

A 0.1 mole
B 0.2mole
C 0.3 mole
D 1.0 mole
E 2.9 moles

Question 375:

(a) State three reasons why air is classified as a mixture.
(b) List two methods that can be used to separate a mixture of iodine crystals and iron filings.