Practice Problem 5

Calculate the mole fractions of both the solute and the solvent in a saturated solution of hydrogen sulfide in water at 20^oC and 1 atm.

Solution

In the previous exercise, we calculated the number of moles of H₂S in this solution.

To determine the mole fraction of the solute and solvent we also need to know the number of moles of water in this solution.

The mole fraction of the solute is the number of moles of H₂S divided by the total number of moles of both H₂S and H₂O.

The mole fraction of the solvent is the number of moles of H₂O divided by the moles of both H₂S and H₂O.

Note that the sum of the mole fractions of the two components of this solution is 1.

X _solute + X_solvent = 0.002 + 0.998 = 1