Answer to Question #131057 in Chemistry for al

Question

The amount of CO2 in the ocean is approximately 280 ppm. What is the mole fraction of CO2 in a liter of ocean water?

Answer 1

Dencity of ocean water is 1027 kg/m³

280 ppm of CO₂ is 280 mg/l and approximately 280 mg/kg

M (CO₂) = 44 g/mol

Moles/kg of CO₂ = 280 mg/kg / 44 g/mol / 1000 = 6.36 x 10^-3 mol/kg CO₂

Molarity = 6.36 x 10^-3 mol/kg CO₂ x 1027 kg/l = 6.53 M

Mass of ocean water is 1000 х 1027 kg/m³ = 1 027 000 g

M (H₂O) = 18 g/mol

Moles of ocean water are 1 027 000 g / 18 g/mol = 57 056 moles

Mole fraction of CO2 in ocean water is: 6.53 / (6.53+57 056) = 0.0001 = 1 x 10^-4