Required Practicals

Question 1

Making crystals

Answer 1

1. Take a base, such as copper oxide, and mix with a heated acid (e.g. concentrated sulphuric acid) to neutralise the base to form a salt solution (copper sulphate)
2. Add excess copper oxide, indicated by unreacted solids at the bottom of the beaker.
3. Filter then heat the solution in an evaporating basin on a beaker of water over a tripod, gauze and Bunsen burner.
4. Once the water has evaporated, dry the crystals produced by placing them on filter paper.

Question 2

Neutralisation/Titration

Answer 2

1. Measure out 25cm3 of the alkali (e.g. sodium hydroxide solution) using a glass pipette and put into a conical flask.
2. Add indicator, such as phenolphthalein, then place flask on white tile
3. Fill burette with an acid to 0cm3. For a rough titration, open the tap to add acid to the alkali, swirling the flask. Once it turns from pink to colourless, it has neutralised
4. Carry out multiple titrations, but when it gets close to neutralising, add drops at a time and swirl until it remains colourless.
5. Measure volume of acid required to neutralise the alkali. (READ BOTTOM OF CURVE/MENISCUS) Use the equation conc = mol/vol to work out concentration of acid.

Question 3

Electrolysis

Answer 3

1. Pour 50cm3 of copper 2 chloride solution into beaker.
2. Place plastic petri dish over beaker with two holes
3. Insert a carbon graphite rod into each hole (because carbon graphite electrodes are inert) so that they don’t touch each other
4. Attach crocodile clips to the rods and connect them to a low voltage power supply
5. Turn on the supply and record results
6. Repeat with different solutions

Question 4

Temperature changes

Answer 4

1. Measure 30cm3 of dilute hydrochloric acid using a measuring cylinder
2. Transfer into polystyrene cup and place cup in beaker to stop falling over
3. Use thermometer to measure temp of acid
4. Use a measuring cylinder to measure 5cm3 of sodium hydroxide solution and place into cup
5. Place a lid over cup and insert the thermometer through the hole in the lid