GCSE Chemistry Required Practical: Purifying Water
Contents
Key Stage 4
Meaning
Analysis and purification of water from different sources.
Method
A sample of rain water, sea water and bottled 'spring' water should be supplied.
Testing the pH
- Using a clean pipettes to add 2ml of a water sample to a test tube and label it.
- Add 2 drops of pH Indicator to the test tube and record the colour and pH.
- Repeat steps 1 and 2 for each water sample.
Finding Solutes
- Measure the mass of a Watch Glass.
- Add 4ml of a water sample to the watch glass.
- Add 150ml of tap water to 250ml beaker.
- Place the watch glass on top of the beaker.
- Heat the water in the beaker to boiling and keep boiling until all the water in the watch glass has evaporated.
- Allow the water to cool and then observe the watch glass for any remaining solutes.
- Measure the mass of the Watch Glass with solutes and subtract the mass of the watch glass to find the mass of the solutes.
- Repeat the experiment for each water sample using a clean watch glass each time.
Purifying Water
- Add 40ml of a water sample to a 100ml conical flask.
- Attach a bung and delivery tube to the top of the conical flask.
- Place a Test Tube in a cold water bath.
- Heat the water sample in the conical flask and arrange the delivery tube to pass the water vapour into the cold test tube where it will condense.
- Use the water collected to repeat tests for pH and finding solutes.
- Repeat 1-5 for each water sample.