1. C3 Chemicals in Our Lives – Risks & Benefits Lesson 6: Reacting Alkalis

2. Objectives MUST explain why the industrial manufacture of alkalis increased in the 19 th century SHOULD remember which substances are classed as alkalis COULD remember the patterns of reactions of alkalis with acids

3. Key Words You need to be able to define the following: pH Soluble Base

4. Textbook Answers 1)Iron; textiles; glass; pottery. 2)The growing industry required more alkali than could be provided from burning plants. 3)Alkalis – potassium hydroxide, sodium carbonate. Salts: –sodium chloride, potassium nitrate, calcium chloride, ammonium sulfate. 4)a) Potassium chloride and water. b) Sodium nitrate, water and carbon dioxide. 5)a) calcium hydroxide + sulfuric acid  calcium sulfate + water b) potassium carbonate + hydrochloric acid  potassium chloride + water + carbon dioxide.

5. Worksheet Answers

6. Practical Answers Part A 2)a) Depends on indicator used; pH less than 7. b) Depends on indicator used; pH greater than 7. c) Should include sodium hydroxide, sodium carbonate, ammonia, calcium hydroxide. Part B 1)When an alkali takes away the acidity of an acid. 2)Similarity – hydroxides and carbonates neutralise acids. Difference – carbonates fizz/give off a gas when they react, hydroxides do not. Part C 1)Sodium chloride 2) sodium hydroxide + hydrochloric acid  sodium chloride + water

7. Practical Answers Part D 1)sodium carbonate + hydrochloric acid  sodium chloride + carbon dioxide + water 2)hydroxide + acid  salt + water; carbonate + acid  salt + carbon dioxide + water 3)a) potassium hydroxide + nitric acid  potassium nitrate + water b) sodium hydroxide + sulfuric acid  sodium sulfate + water c) sodium carbonate + sulfuric acid  sodium sulfate + carbon dioxide + water d) potassium carbonate + nitric acid  potassium nitrate + carbon dioxide + water e) calcium hydroxide + hydrochloric acid  calcium chloride + water