Chem Practicals 1 & 2

Question 1

Copper sulfate crystals

Answer 1

1. Pour cultures acid in conical flask & warm in a water bath
2. Add spatula of copper oxide powder to acid & stir with rod
3. Continue adding copper oxide until it’s in excess
4. Filter mixture to remove excess
5. Pour filtrate into evaporating basin
6. Heat copper sulfate solution
7. Pour solution in a watch glass & allow water to evaporate

Question 2

Making salts from acids & alkalis

Answer 2

1. Use burette to add 50cm3 of hydrochloric acid to conical flask
2. Estimate & record pH
3. Put piece of universal indicator paper onto white tile
4. Dip end of rod into liquid & tap onto universal indicator
5. Wait 30s, match colour to pH colour chart
6. Measure 0.3G calcium hydroxide powder onto piece of paper
7. Add the powder to conical flask, stir, estimate & record pH of mixture
8. Repeat so u add 2.4g of the powder in total to the acid

Question 3

Purifying copper using copper electrodes

Answer 3

1. Use copper foil to use as electrodes & clean with emery paper. Label anode & cathode
2. Measure & record mass of electrodes
3. Half fill beaker with copper sulfate
4. Turn power on & adjust VR to 0.2A
5. Record current
6. Turn off power & removes electrodes from beaker. Rinse with distilled water & dip into propane
7. Measure & record masses of electrodes. Repeat using different currents

Question 4

Electrolysis of copper sulfate using inert electrodes

Answer 4

1. Set up circuit
2. Turn power on
3. Observe what happens at each electrode
   
   • cathode-> copper deposits form
   • anode-> oxygen bubbles

Question 5

Effects of changing condition on rate of reaction

Answer 5

1. Measure 50cm3 of 0.2M hydrochloric acid with measuring cylinder & pour into conical flask.
2. Set up gas collection apparatus by filling measuring cylinder with tap water, placing bung on top & upturning in trough of water.
3. Remove bung from upturned
   measuring cylinder.
   4.Insert delivery tube into upturned measuring cylinder in trough.
4. Measure 5g of marble chips-> top pan balance.
5. Add to acid, attaching bung & delivery tube so gas is collected.
6. Start stopwatch for 60s & measure volume of gas produced.
7. Repeat for 0.4M and 0.6M

Question 6

Monitoring colour change

Answer 6

1.Measure 10cm3 of sodium thiosulfate solution & 40cm3 of eater into 250cm3 conical flask.
2. Measure 5cm3 of dilute hydrochloric acid into test tube.
3. Draw black cross on white paper
4. Add hydrochloric acid into conical flask & start stopwatch
5. Look down from above & time how long it takes X to “disappear”.
6. Record in table.
Repeat with 3 other temperatures.