Question

An aqueous solution is labeled as 0.25 m NaCl.  What is the mole fraction of the solute in this solution?  Show all calculations leading to an answer.

Could someone please show me step by step on how to solve this problem?

Answer 1

Use the formulas that define molality and mole fraction.

\(\sf molality=\dfrac{moles~of~solute}{kg~of~solvent}\)

\(\sf mole~fraction~of~NaCl=\chi_{NaCl}=\dfrac{moles~of~NaCl}{moles~of~NaCl+moles~of~water}\)

i feel like they should've given you a way to find the mass of water

Answer 2

i guess you can assume 0.25 moles of NaCl and 1 kg of water