Question

What is the mole fraction of Substance B in a mixture that is 50.0% weight of substance A in Substance B (Molar Mass of A = 60.06 g/mol; Molar mass of B = 148.16 g/mol)?​

Answer 1

we assume a total mass of 100.0 g, although any mass could be assumed.

This means that we have 50.0 g of substance A and 50.0 g of substance B.

We can then calculate the moles present by dividing each by its molecular weight.

We have 0.833 moles substance A and 0.388 moles substance B.

so we have 1.22 moles total.

To find the mole fraction, we divide the moles of substance B by total number of moles:

x= 0.338/1.22 = 0.318

i.e. The mole fraction for Substance B is 0.318