Question

calculate the mole fraction of MgCl2 in 0.250 L of a 0.311 M MgCl2 solution. (Assume the volume change due to the addition of solute is negligible)

the answer is 0.0530... i just need the work to show how this answer was gotten

Being told it needs two solutes... it doesn't have that. This is the question word for word from the homework

Answer 1

let us consider 1L of solution

Molarity = number of moles of solute per liter of solution

0.311M MgCl2 = 0.311mole MgCl2 in 1L of solution

number of moles of MgCl2 in 0.250L of solution = (0.311mol/1L)×0.250L = 0.07775mol

mass of 0.250L water = 250g

Number of moles = mass /molar mass

Number of moles of water = 250g/18.02g/mol = 13.873mol

Total moles = 0.07775mol + 13.873mol = 13.951mol

mole fraction = number of moles / Total moles

mole fraction of MgCl2 = 0.07775mol / 13.951mol = 0.005573

this is the answer if not satisfied please comment