Question

How would you prepare 1.00 L of an alchol water solution that is 5.00 vol % alchol.

Answer 1

5.00% v/v is 5.00 mL alcohol/100 mL soln which is 50.0 mL alcohol/1000 mL soln. To do this accurately, you would add 50.0 mL alcohol to a 1L volumetric flask and add water to the mark on the flask. Then shake and mix thoroughly. Note that I did NOT say to add 50.0 mL alcohol to 950 mL H2O. The correct procedure gives you 1 L solution; the latter procedure gives you less than 1 L soln; i.e., 950 mL H2O + 50.0 mL alcohol is NOT equal to 1000 mL.