Question

The mole fraction of co2 in a certain solution with h2o as the solvent is 3.6 × 10−4. What is the % mass of co2 in this solution?

Answer 1

• The % mass of CO₂ in this solution is 0.088%

Step-by-step explanation:

1) Basis

Assume 100 moles of solution

2) Number of moles of CO₂ (solute)

• number of moles of solute = mole fraction × number of moles of solution

• 3.6 × 10⁻⁴ × 100 = 0.036 moles of CO₂

3) Number of moles of H₂O (solvent)

• mole fraction of solvent = moles of solution - moles of solvent

• number of moles of solvent = 100 - 0.036 = 99.964 moles of H₂O

4) Mass of solution

a) Mass = number of moles × molar mass

b) Mass of CO₂ = 0.036 mol × 44.01 g/mol = 1.584 g

c) Mass of H₂O = 99.964 mol × 18.015 g/mol = 1,800.85 g

d) Mass of solution = mass of solute + mass of solvent = 1.584 g + 1,800.85 g = 1,802.435 g

5) Percent mass of CO₂, %

• % = (mass of solute / mass of solution) × 100 =

• % = (1.584 g / 1,802.435g) × 100 = 0.088% ← answer