Question

At 25.0 ⁰C the henry's law constant for hydrogen sulfide(H2S) gas in water is 0.087 M/atm. Caculate the mass in grams of H2S gas that can be dissolved in 400.0 ml of water at 25.00 C and a H2S partial pressure of 2.42atm.

Answer 1

Answer: The mass of hydrogen sulfide that can be dissolved is 2.86 grams.

Step-by-step explanation:

Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the gas.

To calculate the molar solubility, we use the equation given by Henry's law, which is:

`C_(H_2S)=K_H* p_(liquid)`

where,

`K_H` = Henry's constant =
`0.087M/atm`

`p_(H_2S)` = partial pressure of hydrogen sulfide gas = 2.42 atm

Putting values in above equation, we get:

`C_(H_2S)=0.087M/atm* 2.42atm\\\\C_(H_2S)=0.2105M`

To calculate the mass of solute, we use the equation used to calculate the molarity of solution:

`\text{Molarity of the solution}=\frac{\text{Mass of solute}* 1000}{\text{Molar mass of solute}* \text{Volume of solution (in mL)}}`

We are given:

Molarity of solution = 0.2105 M

Molar mass of hydrogen sulfide = 34 g/mol

Volume of solution = 400.0 mL

Putting values in above equation, we get:

`0.2105M=\frac{\text{Mass of hydrogen sulfide}* 1000}{34g/mol* 400.0mL}\\\\\text{Mass of }H_2S=(0.2105* 34* 400)/(1000)=2.86g`

Hence, the mass of hydrogen sulfide that can be dissolved is 2.86 grams.