Mole fraction of MgCl2 = moles of MgCl2 / total moles of all components
First, calculate the moles of MgCl2:
moles of MgCl2 = mass of MgCl2 / molar mass of MgCl2
moles of MgCl2 = 1.2722 g / 95.21 g/mol
moles of MgCl2 = 0.01337 mol
Next, calculate the moles of water:
moles of water = mass of water / molar mass of water
moles of water = 27.8002 g / 18.015 g/mol
moles of water = 1.5435 mol
Now, calculate the total moles of all components:
total moles = moles of MgCl2 + moles of water
total moles = 0.01337 mol + 1.5435 mol
total moles = 1.5569 mol
Finally, calculate the mole fraction of MgCl2:
mole fraction of MgCl2 = 0.01337 mol / 1.5569 mol
mole fraction of MgCl2 ≈ 0.0086