Experiment exam questions

Question 1

Why do you round to the nearest second when stopwatch has accuracy of 0.01s when doing the rates of reaction by observing cross experiment?

Answer 1

You can’t judge the exact moment to the nearest 0.01s

Question 2

Suggest one reason why Tollens’ reagent is used as the oxidising agent in the specific test for aldehydes rather than the less expensive acidified potassium dichromate(VI).

Answer 2

Dichromate(VI) will also oxidise / give a positive test with alcohols

Question 3

Suggest why it is necessary to use two solvents in thin layer chromatography

Answer 3

If some of the chemicals being tested don’t dissolve/separate with one of the solvents

Two chemicals have same Rf value in one of the solvents