What is the concentration off alcohol solution that was prepared by dissolving 40cm3 ethanol in 160cm3 water

To find the concentration of the alcohol solution, you need to calculate the volume of ethanol in the solution relative to the total volume of the solution.

First, let's find the total volume of the solution. Add the volume of ethanol (40 cm³) and the volume of water (160 cm³) together:
Total volume of solution = volume of ethanol + volume of water
Total volume of solution = 40 cm³ + 160 cm³
Total volume of solution = 200 cm³

Now, divide the volume of ethanol by the total volume of the solution and multiply by 100 to express it as a percentage:
% concentration of ethanol = (volume of ethanol / total volume of solution) × 100
% concentration of ethanol = (40 cm³ / 200 cm³) × 100
% concentration of ethanol = 0.2 × 100
% concentration of ethanol = 20%

Therefore, the concentration of the alcohol solution is 20%.