Answer
0.281
Work Step by Step
We are told we have equal masses of ethanol and H2O. Assuming we have 100g of ethanol and 100g of H2O we convert both to moles. The molar mass of H2O is 18g/mol and the molar mass of ethanol C2H5OH is 46g/mol. Converting both masses to moles we have
For water:
100g * (1mol/18g) = 5.556 moles
For ethanol
100g* (1mol/46g) = 2.17 moles
Then, the mole fraction of ethanol would be:
2.17 / (2.17 + 5.556) = 0.281
