Question

A solution is prepared by dissolving 150 mL of ethanol in enough water to make a 500 mL solution. What is the percent by volume of ethanol in the solution?  

a.10%

b.30%
c.70%

Answer 1

The percent by volume of ethanol in the solution 30% ((150/500)*100%) based on the Law of Conservation of Mass. The object's mass before a reaction and after a reaction is equal according to the Law of Conservation of Mass. The dissolved ethanol become the part of the solution but it does not decrease its volume.