1. C5.5 Salts from insoluble bases

2. Specification link AQA Specification links
Acids are neutralised by bases (e.g., insoluble metal hydroxides and metal oxides) to produce salts and water.
The particular salt produced in any reaction between an acid and a base depends on:
• The acid used (hydrochloric acid produces chlorides, nitric
acid produce nitrates, sulfuric acid produce sulfates)
• The positive ions in the base.
4.2.3 Required practical 1: preparation of a pure, dry sample of a soluble salt from an insoluble oxide or carbonate.

3. Specification link

4. Practical 1 - Chances for assessment
Students work on paper. File in a separate folder for evidence.
Evidence – equipment list, risk assessment, observations

5. Big Q: What happens when an acid and a base react?
Saturday, 17 November 2018Saturday, 17 November 2018
Big Q: What happens when an acid and a base react? LO
• the reaction between an acid and a base
• how to prepare pure, dry crystals of the salts formed in neutralisation reactions between acids and insoluble bases
• how to predict products from given reactants
• how to use the formulae of common ions to deduce the formulae of salts.

6. Reaction of Bases with Acids Neutralisation
Acid + Base
Salt + Water
For example
6HCl(aq) + Fe2O3(s)
2FeCl3(aq) + 3H2O(l)
Hydrochloric + Iron (III)
Acid Oxide
Iron (III) Water
Chloride

8. Required Practical 1 - ALL
Preparation of copper sulphate

9. Practical Time: Making copper sulfate
CuO(s) + H2SO4(aq)
CuSO4(aq) + H2O(l)
Copper + Sulfuric Copper + Water
Oxide Acid Sulfate

10. Making a Copper Salt Select equipment appropriate to the experiment Carry out practical correctly and safely

12. Arrange it Put the filtrate into a conical flask
Stir it until it is dissolved
Pour the solution into a petri dish and leave until crystals form
Put 20cm3 of warm sulphuric acid into a beaker
Filter out any unreacted oxide
Boil the filtrate for 2 Mins to evaporate some water
Add 1 spatula of copper oxide

13. Arrange it Put 20cm3 of warm sulphuric acid into a beaker
Add 1 spatula of copper oxide
Stir it until it is dissolved
Filter out any unreacted oxide
Put the filtrate into a conical flask
Boil the filtrate for 2 Mins to evaporate some water
Pour the solution into a petri dish and leave until crystals form

14. prompts warm sulphuric acid measuring cylinder beaker
spatula copper oxide
Stir dissolved
Filter funnel filter paper unreacted oxide
conical flask Boil
evaporate
petri dish crystals

15. Method
Measure 20cm3 of warm sulphuric acid in a measuring cylinder and put it into a beaker
Add 1 spatula of copper oxide
Stir it using a stirring rod until it is dissolved
Filter out any unreacted oxide using a funnel and filter paper
Put the filtrate into a conical flask
Boil the filtrate over a Bunsen flame for 2 Mins to evaporate some water
When it is cool enough to touch, pour the solution into a petri dish and label so crystals can be formed

16. Apparatus and risk assessment
List the apparatus you will need to measure, heat, filter and evaporate a solution.
Make a table with 3 headings: Hazard, risk and precaution/ emergency action. You are using various dangerous chemicals and techniques – what will you do to keep safe? Write these down in your table.
Evidence: Risk assessment, written / drawn observations

17. Step 1: Preparation
Clear desks and make sure all bags and stools are under benches;
Get into pairs;
Collect the following equipment:
safety goggles bunsen burner
heat proof mat tripod
gauze beaker
Evaporating dish clay triangle
tongs spatula
filter paper funnel
Boiling tube

18. Step 2: Chemicals One person from each desk come and collect:
Copper oxide
Sulfuric acid
Set up bunsen burner

19. Step 3: Complete Practical
Gently heat 15ml sulfuric acid in a water bath for 2-3 minutes.
Add copper oxide, one spatula at a time, until no more will dissolve – you will see excess black powder in tube. Make sure you stir solution thoroughly.
Allow tube to cool and then pass through filter paper into flask – this should remove any black copper oxide from your solution.
Heat flask on Bunsen with 2-3 anti-bump granules. TURN OFF WHEN BOILS.
Use a test tube holder to pour the hot liquid into the evaporating dish and write up your practical - equipment list, risk assessment, observations.
You should see crystals forming round the edge in 5 minutes.
Observation – describe / draw the copper sulphate

20. Progress check