Question

Find the mole fraction of Methanol CH3OH and water in a solution prepared by dissolving 4.5 g of alcohol in 40 g of H2O.

Answer 1

mass of alcohol (CH3OH) = 4.5g

molar mass of CH3OH = 32g/mol

so, mole of CH3OH, n = 4.5/32 mol

= 9/64 mol = 0.14 mol

again, mass of water = 40g

molar mass of water = 18g/mol

so, mole of water = 40/18

= 20/9 ≈ 2.22 mol

now mole fraction of methanol= mole of methanol/(mole of methanol + mole of water)

= 0.14/(0.14 + 2.22)

= 0.14/2.36

= 0.059 ≈ 0.06

hence, mole fraction of methanol is 0.06

Answer 2

Answer:

mass of alcohol (CH3OH) = 4.5g

molar mass of CH3OH = 32g/mol

so, mole of CH3OH, n = 4.5/32 mol

= 9/64 mol = 0.14 mol

again, mass of water = 40g

molar mass of water = 18g/mol

so, mole of water = 40/18

= 20/9 ≈ 2.22 mol

now mole fraction of methanol= mole of methanol/(mole of methanol + mole of water)

= 0.14/(0.14 + 2.22)

= 0.14/2.36

= 0.059 ≈ 0.06

hence, mole fraction of methanol is 0.06

Explanation: