C5.5 Salts from insoluble bases

Specification link AQA Specification links 4.2.2 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.

Specification link

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

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.

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

Required Practical 1 - ALL Preparation of copper sulphate

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

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

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

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

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

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

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

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

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

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

Progress check