Two Rates Experiments

The first reaction

• Start by adding a set volume of dilute hydrochloric acid to a conical flask and carefully place on a mass balance.
• Now add some magnesium ribbon to the acid and quickly plug the flask with cotton wool.
• Start the stopwatch and record the mass on the balance. Take readings of the mass at regular intervals.
• Plot the results in a table and work out the mass lost for each reading. Now you can plot a graph with time on the x axis and mass lost on the y axis.
• Repeat with more concentrated acids. Variables such as the amount of magnesium and the volume of acid used should be kept the same each time to make sure it is a fair test.

The second reaction

• Sodium thiosulfate and hydrochloric acid are both clear solutions. They react together to make a yellow precipitate of sulfur.
• Start by adding a set volume of dilute sodium…