> Mole fraction of ethanol –water system is 0.25. What is percent concentration of ethanol by weight of solution.
To find the percent concentration of ethanol by weight of the solution, we need to know the mass of ethanol in the solution.
Let's assume we have 100 grams of the solution, and the mole fraction of ethanol in the solution is 0.25.
Since the mole fraction of ethanol is 0.25, the mole fraction of water will be 0.75 (1 - 0.25).
We can calculate the mass of ethanol in the solution as follows:
Mass of ethanol = mole fraction of ethanol * total mass of solution
= 0.25 * 100 grams
= 25 grams
Therefore, the solution contains 25 grams of ethanol.
To find the percent concentration of ethanol by weight of the solution, we divide the mass of ethanol by the total mass of the solution and multiply by 100.
Percent concentration of ethanol by weight = (mass of ethanol / total mass of solution) * 100
= (25 grams / 100 grams) * 100
= 25%
So, the percent concentration of ethanol by weight of the solution is 25%.