Answer:
12.7% v/v
Explanation:
The percent by volume (% v/v) expresses the volume of solute dissolved in 100 mL of solution. It can be calculated as follows:
%v/v = volume of solute/volume of solution x 100%
In this problem, the solute is ethanol and the solvent is water. Thus, we have the following data:
volume of solute = 20 mL (ethanol)
volume of solution = volume of solute + volume of solvent = 20 mL + 137 mL = 157 mL
Finally, we introduce the data in the equation:
%v/v = 20 mL/157 mL x 100% = 12.7% v/v
