# Henry's law constant for CO2 in water is 1.6 x 108 Pa at 298 K. Calculate the quantity of CO2 in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298K.

By Ritesh|Updated : November 9th, 2022

The quantity of CO2 in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298K is 1.848 g. Steps to Calculate the quantity of CO2 in 500 mL of soda water:

We know that from Henry's law, pco2 = KHx

x is the amount of carbon dioxide per mole of the carbon dioxide and water mixture.

pco2 = 2.5 atm = 2.5 x 1.01325 x 105 Pa = 2.533125 x 105 Pa

• x = mole fraction = 2.533125 x 105/ 1.67 x 108 = 0.00152
• x = moles of CO2/(moles of CO2 + moles of H2O) ≈ moles of CO2/moles of H2O

as moles of CO2 is negligible in comparison to the number of moles of water.

500 ml of water = 500g of water = 500/18 = 27.78 moles of water.

So, moles of CO2/27.78 = 0.00152 or moles of CO2 = 0.042 moles. Therefore the amount of CO2 in 500 ml of soda water is 0.042 x 44 = 1.848 g.

### Factors affecting Henry’s law Constant

The following variables influence a gas's Henry's law constant value:

• The gas's composition
• What kind of solvent it is
• Temperature & pressure

Limitations of Henry’s Law

• Only when the system's molecules are in an equilibrium state is this law applicable.
• When gases are put under very high pressure, Henry's law does not apply.
• When the gas and the solution engage in chemical reactions with one another, the law is not applicable.

Summary:

## Henry's law constant for CO2 in water is 1.6 x 108 Pa at 298 K. Calculate the quantity of CO2 in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298K.

Henry's law constant for CO2 in water is 1.6 x 108 Pa at 298 K. The quantity of CO2 in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298K is 1.848 g.