Question

The mole fraction of ethanol in water is 0.08 . What is it's molality

Answer 1

0.08=x/x+55.5
=>0.08x+55.5*0.08=x
=>x=4.82m

Answer 2

Answer: 4.83

Explanation: Molality is defined as the number of moles of solute dissolved per kg of solvent.

Mole fraction is the ratio of moles of one component to the total number of moles.

moles of ethanol= 0.08

moles of solution= moles of ethanol + moles of water=1

moles of water= (1-0.08) = 0.92

weight of water=${\text {moles}}\times {molar mass}=0.92\times 18=16.56g=0.01656kg$

$Molality=\frac{0.08moles}{0.01656kg}=4.83$