Question

1.20g of methyl alcohol, CH3OH, are dissolved in 16.8g of water, H20. What is the mole fraction of the solute? a. 0.0386 b. 0.0667 c. 0.0402 d. 0.0348

Answer 1

The mole fraction of the solute can be calculated using the following formula:

mole fraction of solute = moles of solute / (moles of solute + moles of solvent)

To calculate the moles of solute, we first need to convert the given mass of CH3OH to moles using its molar mass:

Molar mass of CH3OH = 12.01 + 3(1.01) + 16.00 = 32.04 g/mol

moles of CH3OH = 1.20 g / 32.04 g/mol = 0.0374 mol

To calculate the moles of water, we divide the given mass of water by its molar mass:

Molar mass of H2O = 2(1.01) + 16.00 = 18.02 g/mol

moles of H2O = 16.8 g / 18.02 g/mol = 0.932 mol

Now we can calculate the mole fraction of solute:

mole fraction of solute = 0.0374 mol / (0.0374 mol + 0.932 mol) = 0.0386

Therefore, the mole fraction of the solute is 0.0386, which is option a.