GCSE Chemistry Required Practical: Concentration and Rate of Reaction

Key Stage 4

Meaning

Investigate how concentration affects the rate of reaction.

Method

Observation of Rate by Opacity

1. Draw a large thick black cross on to a White Tile and place a 100ml Conical Flask on top as shown in the diagram.
2. Measure 10ml of 0.25M Sodium Thiosulphate using a Measuring Cylinder and add to the Conical Flask.
3. Measure 40ml of Water and add to the Conical Flask.
4. Measure 10ml of 2M Hydrochloric Acid using a Measuring Cylinder.
5. Add the 10ml of Hydrochloric Acid to the Conical Flask while starting a stopwatch.
6. Observe the cross from above, through the solution. When the cross is no longer visible through the solution stop the stopwatch and record the time in seconds.
7. Repeat the experiment with 20ml Sodium Thiosulphate and 30ml Water, 30ml Sodium Thiosulphate and 20ml Water, 40ml Sodium Thiosulphate and 10ml Water and 50ml Sodium Thiosulphate.
8. Repeat the same experiment for all ratios of Sodium Thiosulphate and Water a further two times to calculate an average.

Observation of Rate by Gas Produced

This diagram shows a possible setup for measuring the gas given off during an experiment.

1. Set up the apparatus as shown in the diagram.
2. Measure 10ml 2M Hydrochloric Acid using a Measuring Cylinder.
3. Add the Hydrochloric Acid to the Boiling Tube.
4. Add 1 spatula of Marble chips Calcium Carbonate to the Boiling Tube.
5. Attach the bung.
6. Fill the 50ml Measuring Cylinder with water in the tub and hold it over the end of the delivery tube to collect the bubbles.
7. Start a stopwatch and record the volume of gas in the Measuring Cylinder every 10 seconds.
8. Repeat this experiment with 10ml 1M Hydrochloric Acid.