Practicals

Question 1

How can we use Magnesium and Hydrochloric Acid to see the effect of concentration on rate of reaction?

Answer 1

1)Add dilute hydrochloric acid to a flask and place it on a mass balance.
2)Add magnesium ribbon, plug the flask, and start the stopwatch.
3)Record mass readings at regular intervals.
4)Plot results in a table and graph.
5)Repeat with different acid concentrations, keeping magnesium and acid volume constant.
6)Compare graphs.

Question 2

How can we use sodium thiosulfate and hydrochloric acid to see the effect of concentration on the rate of a reaction?

Answer 2

1) Both chemicals are clear solutions.
2) Add dilute sodium thiosulfate to a flask, forming a yellow sulfur precipitate.
3) Place flask on paper with a black cross, add dilute HCl, and start stopwatch.
4) Time how long it takes for the cross to disappear.
5) Repeat with different HCl concentrations, keeping liquid depth constant.
6) Results show higher HCl concentration speeds up the reaction.
7) Higher concentration = faster reaction = quicker cross disappearance.
8) Drawbacks: Can’t generate multiple graphs.