Required Practicals

Question 1

making salts practical (6)

Answer 1

• gently warm the dilute acid using a bunsen burner
• add the insoluble base to the acid a bit at a time until no more reacts (the base is in excess)
• filter out the excess solid to get the salt solution
• for pure, solid crystals, gently heat the solution using a water bath or electric heater to evaporate some of the water
• leave to cool
• crystals that have been formed can be filtered out of the solution

Question 2

making copper sulfate salts

Answer 2

• add insoluble copper oxide to sulfuric acid and stir
• warm gently on a tripod
• solution turns blue as the reaction occurs, showing that copper sulfate is being formed
• excess copper oxide can be seen
• filter the solution to remove excess copper oxide
• evaporate water so that crystals of copper sulfate start to form

Question 3

electrolysis practical (5)

Answer 3

• pour copper sulfate solution into a beaker
• place two graphite rods into the solution, connecting one electrode to the negative terminal of a dc supply and the other to a positive terminal
• fill two small test tubes with more copper sulfate solutions and position a test tube over each electrode
• turn on the power supply and observe what happens
• test any gas produced with a glowing splint