General chemistry question?

Question

You are directed to set up a toxicity study by preparing various concentrations of toxicants. One part asks you to make a .05% solution of acetic acid. Another part asks you to make a .069M solution of HCL. Describe how you would go about making these solutions, using vinegar bought from the grocery store for the acetic acid and a 12 M solution of HCL for the chemistry stock room.

Answer 1

These are simply dilution ratio problems:

Vinegar is approx 5% acetic acid...to get 0.05%, you have to wind up with 5/.05 = 100 vols, so add 1 vol of vinegar to 99 vols of water...eg 10ml vinegar plus 990ml water.

Similarly to reduce 12M HCl to 0.069M, 12/0.069 = 174 , so add 1 vol of acid to 173 vols of water...eg 10ml acid plus 1730ml water. (Problem would have been simpler if 0.060M was needed...that wd require 10ml acid to 1990ml water...right?).