Question

In a 51.0 -g aqueous solution of methanol, CH 4 O , the mole fraction of methanol is 0.260. What is the mass of each component?

Answer 1

Total mass of aqueous solution of methanol = 51.0 g

Let the mass of methanol be x g.

Hence, mass of water = (51.0 - x) g.

Given that the mole fraction of methanol , 0.260

Molar mass of water = 18.01 g/mol

Hence, number of moles of water in the mixture is

Molar mass of methanol = 32.04 g/mol

Hence, number of moles of methanol in the solution is

Now, we can write the equation for the mole fraction of methanol as follows:

Hence, the amount of methanol in the solution is x= 19.6 g approximately.

Hence, the amount of water can be calculated as

Hence, there the mass of methanol component is 19.6 g and mass of water component is 31.4 g approximately.

Verification:

Moles of water =

Moles of methanol =

Hence, mole fraction of methanol is

Hence, our answer is correct.