Question

A solution is made using 200.0 mL of methanol (density 0.792 g/mL) and 985.1 mL of water (density 1.000 g/mL). What is the mass percent of the methanol

Answer 1

Answer: The mass percent of methanol in solution is 13.85 %

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

• For water:

Density of water = 1.000 g/mL

Volume of water = 985.1 mL

Putting values in above equation, we get:

$1.000g/mL=\frac{\text{Mass of water}}{985.1mL}\\\\\text{Mass of water}=(1.000g/mL\times 985.1mL)=985.1g$

• For methanol:

Density of methanol = 0.792 g/mL

Volume of methanol = 200.0 mL

Putting values in above equation, we get:

$0.792g/mL=\frac{\text{Mass of methanol}}{200.0mL}\\\\\text{Mass of methanol}=(0.792g/mL\times 200.0mL)=158.4g$

To calculate the mass percent of methanol, we use the equation:

$\text{Mass percent of methanol}=\frac{\text{Mass of methanol}}{\text{Mass of solution}}\times 100$

Mass of solution = [158.4 + 985.1] g = 1143.5 g

Mass of methanol = 158.4 g

Putting values in above equation, we get:

$\text{Mass percent of methanol}=\frac{158.4g}{1143.5g}\times 100=13.85\%$

Hence, the mass percent of methanol in solution is 13.85 %