Question

How do you calculate mole fraction of solute?

Answer 1

To calculate mole fraction of solute you first calculate the moles of the solute and then you divide that by the total number of moles of solute and solvent.

Explanation:

The mole fraction of solute is:
moles of solute divided by total moles of solute and solvent

The symbol for the mole fraction is the lower-case Greek letter chi, χ. You will often see it with a subscript: χsolute is an example.

Example #1: 0.100 mole of NaCl is dissolved into 100.0 grams of pure H2O. What is the mole fraction of NaCl?

Solution: We will calculate the number of moles of water ( solvent)

100.0 g / 18.0 g mol-1 = 5.56 mol of H2O

Add that to the 0.100 mol of NaCl = 5.56 + 0.100 = 5.66 mol total

Mole fraction of NaCl = 0.100 mol / 5.66 mol = 0.018

What is the mole fraction of the H2O?

5.56 mol / 5.66 mol = 0.982

Simple, and analytical explanation on this website: https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/solutions-12/concentration-units-93/mole-fraction-and-mole-percent-402-1960/