calculate the mass

Question

At 25.0 °C the Henry's Law constant for sulfur hexafluoride (SF6) gas in water is 2.4 x 10^-4 M/atm. Calculate the mass in grams of SF6 gas that can be dissolved in 800. mL of water at 25.0 °C and a SF6 partial pressure of 0.96 atm.

Round your answer to 2 significant digits.

Answer 1

Henry's Law: C = kP

C = concentration = ?

k = Henry's constant = 2.4x10^-4 M/atm

P = partial pressure of the gas = 0.96 atm

Solving for C:

C = (2.4x10^-4 M/atm)(0.96 atm) = 2.30x10^-4 M

Molar mass SF₆ = 146 g / mol

Mass of SF₆ = 2.30x10^-4 mols / L x 0.800 L x 146 g / mol = 0.027 g SF₆ (2 sig. figs.)