1.20g of methyl alcohol, CH3OH, are dissolved in 16.8g of water, H2O. What is the mole fraction of the solute?

0.0386

Explanation:

To make a solution, we need a certain amount of the solute to be dissolved in the solvent. The solvent is the carrier medium usually water in traditional wet chemistry.

Now, in this particular question, it should be known that methyl alcohol is the solute, while water is the solvent.

We need to calculate the mole fraction of the solute as asked by the question. Now what we do is to find the number of moles of each, add together, then divide the number of moles of methyl alcohol by the sum of the moles of both.

Firstly, we calculate the number of moles of methyl alcohol present. This is mathematically equal to dividing mass by molar mass

Molar mass of methyl alcohol (CH3OH) is 12 + 4 (1) + 16 = 32g/mol

The number of moles is thus 1.2/32 = 0.0375 moles

Now, we calculate the number of moles of water. The molar mass of water is 18g/mol

The number of moles of water is thus 16.8/18 = 0.93333

The mole fraction of the solute is thus:

0.0375 / (0.0375 + 0.9333) = 0.0386

The mole fraction of the solute, methyl alcohol, is 0.0387

Explanation:

Step 1: Data given

Mass of methyl alcohol = 1.20 grams

Molar mass of methyl alchol = 32.04 g/mol

Mass of water = 16.8 grams

Molar mass of water = 18.02 g/mol

Step 2: Calculate number of moles of methyl alcohol

Number of moles methyl alcohol = Mass / molar mass

Number of moles methyl alcohol = 1.20 grams / 32.04 grams

Number of moles methyl alcohol = 0.0375 moles

Step 3: Calculate number of moles of water

Moles H2O = 16.8 grams / 18.02 g/mol

Moles H20 = 0.932 moles

Step 4: Calculate total number of moles

Total number of moles = moles CH3OH + moles H2O = 0.0375 moles + 0.932 moles = 0.9695 moles

Step 5: Calculate mole fraction of the solute

Solute = methyl alchol

(Solvent = water)

Mole fraction = 0.0375 moles / 0.9695 moles

Mole fraction = 0.0387

The mole fraction of the solute, methyl alcohol, is 0.0387