Question

Calculate the mole fraction of ethyl alcohol and water in a solution in which 46 g of ethyl alcohol and 180 g of water are mixed together.

Answer 1

Given: Mass of ethyl alcohol (C₂H₅OH) = 46 g

Mass of water (H₂O) = 180 g

Molar mass of ethyl alcohol = 46 g/mol

Molar mass of water = 18 g/mol

Moles of ethyl alcohol = `46/46` = 1 mol

Moles of water = `180/18` = 10 mol

Total moles = 1 + 10 = 11

Mole fraction of ethyl alcohol:

`X_"ethyl alcohol" = 1/11 = 0.0909`

Mole fraction of water:

`X_"Water" = 10/11 = 0.9091`

∴ The mole fraction of ethyl alcohol is 0.091 and the mole fraction of water is 0.909.