Question

Discussion Questions

1. Provide three reasons why a theoretical yield may differ from an experimental yield even when properly following this procedure.

2. When determining the limiting reactant is it reasonable to make the determination that water is not the limiting reactant without calculations. Why or why not?

3. How would the results be affected if the alum was not weighed to a constant mass during the step 6 of the second week’s procedure?

4. If your starting source of aluminum was a coke can would the procedure need to change? Explain your answer. Would you expect the theoretical yield to be the same, higher or lower?

5. The aluminum weigh boat is thin. Would you expect the length of time needed to dissolve the aluminum to change if an aluminum sphere with the same mass was used? Explain your answer.

Answer 1

Q1.

Theoretical yield will tpically fail due to:

- Mishandling of material

- Incorrect reading/use of devices

- Incorrect ratios/stoichiometric calculations

Q2.

Depends on the type of reaction, but since water is readily available, and it is used as a solvent, we can assume this is always in excess

Q3.

If we do not weight this at constant mass, then, expect a higher mass ( incorrect) of alum, due to humidity considered

Q4.

You will need to remove all cover color material.

Exect an easier approach, since aluminium makes most of the cna, i.e. higher than 99%

Q5.

The flat/thin aluminium should take LESS time, du eto higher surface area