Question

At STP 10 grams of CO can be dissolved in 3 L of water. Calculate the solubility of carbon monoxide at 200kPa.

Answer 1

Answer : The solubility of carbon monoxide gas at pressure 200 kPa is, 6.579 g/L

Explanation :

According top the Henry's Law, the solubility of a gas in a liquid is directly proportional to the pressure of the gas.

`S\propto P`

or,

`(S_1)/(S_2)=(P_1)/(P_2)`

where,

`S_1` = initial solubility of gas =
`(10g)/(3L)`

`S_2` = final solubility of gas = ?

`P_1` = initial pressure of gas = 101.325 kPa (at STP)

`P_2` = final pressure of gas = 200 kPa

Now put all the given values in the above formula, we get the final solubility of the gas.

`((10g)/(3L))/(S_2)=(101.325kPa)/(200kPa)`

`S_2=6.579g/L`

Therefore, the solubility of carbon monoxide gas at pressure 200 kPa is, 6.579 g/L

Answer 2

moles CO = 10 g x 1mol 28g = 0.357 moles in 3 L = 0.119 mol/L at STP
P1/n1 = P2/n2
101.325 kPa/0.119 = 200 kPa/n2
n2 = 0.235 moles/L = 0.235mol x 28g/mol = 6.6g/L (assuming no change in temp)