What is the mole fraction of ethanol, C2H5OH, in an aqueous solution that is 50.0% ethanol by mass?

0.282

assume 1000g

molesEthanol=500/46
molesH2O=500/18

mole fractionEthanol=moleEthanol/total moles
= (500/46)/(500/46+500/18)
= 1/(1+46/18)

To find the mole fraction of ethanol, C2H5OH, in an aqueous solution, you need to understand the concept of mole fraction and how to calculate it.

Mole fraction is a way to express the concentration of a component in a mixture. It is defined as the ratio of the moles of a component to the total moles of all components in the mixture.

To calculate the mole fraction of ethanol, you need to determine the number of moles of ethanol and the number of moles of water in the solution.

1. Determine the mass of the solution:
If the solution is 50.0% ethanol by mass, it means that 50.0 grams out of every 100 grams of the solution is ethanol. So if we assume we have 100 grams of the solution, the mass of ethanol in the solution is 50.0 grams.

2. Convert the mass of ethanol to moles:
To calculate the moles of ethanol, you need to know the molar mass of ethanol. The molar mass of C2H5OH is approximately 46.07 g/mol. Divide the mass of ethanol by its molar mass to find the number of moles:
moles of ethanol = mass of ethanol / molar mass of ethanol

3. Determine the mass of water in the solution:
Since the solution is 50.0% ethanol by mass, the remaining 50.0 grams of the solution must be water.

4. Convert the mass of water to moles:
To calculate the moles of water, you need to know the molar mass of water, which is approximately 18.02 g/mol. Divide the mass of water by its molar mass to find the number of moles:
moles of water = mass of water / molar mass of water

5. Calculate the total moles in the solution:
The total number of moles in the solution is the sum of the moles of ethanol and water:
total moles = moles of ethanol + moles of water

6. Calculate the mole fraction of ethanol:
The mole fraction of ethanol is the ratio of the moles of ethanol to the total moles in the solution:
mole fraction of ethanol = moles of ethanol / total moles

Follow these steps using the provided information to find the mole fraction of ethanol in the aqueous solution.

Calculate yourself .I hope u all have got brain...Right.!!