End of chapter exercises

Give one word for each of the following descriptions:

1. the change in phase of water from a gas to a liquid

2. a charged atom

3. a term used to describe the mineral content of water

4. a gas that forms sulphuric acid when it reacts with water

Match the information in column A with the information in column B by writing only the letter (A to I) next to the question number (1 to 7)

Explain the difference between a weak electrolyte and a strong electrolyte. Give a generalised equation for each.

What factors affect the conductivity of water? How do each of these affect the conductivity?

For each of the following substances state whether they are molecular or ionic. If they are ionic, give a balanced reaction for the dissociation in water.

1. methane (\(\text{CH}_{4}\))

2. potassium bromide

3. carbon dioxide

4. hexane (\(\text{C}_{6}\text{H}_{14}\))

5. lithium fluoride (\(\text{LiF}\))

6. magnesium chloride

Three test tubes (X, Y and Z) each contain a solution of an unknown potassium salt. The following observations were made during a practical investigation to identify the solutions in the test tubes:

A: A white precipitate formed when silver nitrate (\(\text{AgNO}_{3}\)) was added to test tube Z.

B: A white precipitate formed in test tubes X and Y when barium chloride (\(\text{BaCl}_{2}\)) was added.

C: The precipitate in test tube X dissolved in hydrochloric acid (\(\text{HCl}\)) and a gas was released.

D: The precipitate in test tube Y was insoluble in hydrochloric acid.

1. Use the above information to identify the solutions in each of the test tubes X, Y and Z.

2. Write a chemical equation for the reaction that took place in test tube X before hydrochloric acid was added.

(DoE Exemplar Paper 2 2007)