Question

If you fail to stir the benzoic acid and lauric acid in the test tube, will the molecular weight that you calculate for the benzoic acid be too high or too low? Why?

Answer 1

If you fail to stir the benzoic acid and lauric acid in the test tube, the molecular weight that you calculate for the benzoic acid be too high.

Explanation:

The more dense liquid is benzoic acid, the freezing point of just the benzoic acidwould be measured, as the two acids are not mixed in solution. The freezing point of the benzoicacid is higher than the freezing point of the solution of both acids. This in turn leads to a smaller calculated freezing point depression. This would indicate a smaller molality of benzoic acid thanthe actual value of the molality of benzoic acid of the solution. This smaller molality of benzoicacid would then indicate fewer moles of benzoic acid present in the solution. When molecular mass is calculated based on this, the calculated value for the molecular mass of benzoic acidwould increase, because the number of grams present is being divided by a smaller number of moles.