Answer:

If 60 ml of ethanol is diluted to a final volume of 400 ml, you create a 35 % ethanol solution.

First, realize that you creating a solution with that contains a polar solute (ethanol) with a polar solvent (water). Remember that "like dissolves like."

If you pour 60 ml of ethanol in a volumetric flask, you add 340 ml of water to dilute this solution to a final volume of 400 ml.

Volumetric flasks are designed to make or dilute solutions to specified final volume.

Since you have 60 ml of ethanol in a total solution of 400 ml, the percentage of ethanol is 35 %.

Explanation:

This result is obtained in the following manner.

ml/400. ml. = .35

.35 x 100% = 35 %