Question

The partial pressure of CO2 inside a bottle of soft drink is 4.0 atm at 25°C. The solubility of CO2 is 0.12 mol/L. When the bottle is opened, the partial pressure drops to 3.0 ✕ 10-4 atm. What is the solubility of CO2 in the open drink? Express your answer in grams per liter. 

Answer 1

We can solve this problem by using Henry's law. 
Henry's law states that the amount of dissolved gas is proportional to its partial pressure.
$C=kP$
C is the solubility of a gas.
k is Henry's law constant.
P is the partial pressure of the gas.
We can calculate the constant from the first piece of information and then use Henry's law to calculate solubility in open drink.
0.12=4k
k=0.03
Now we can calculate the solubility in open drink.
$C_o=kP_o$
$C_o=0.03 \cdot 3\cdot 10^{-4}=0.09\cdot 10^{-4} \frac{mol}{L}$
Now we need to convert it to g/L. One mol of CO2 is 44.01g. 
The final answer is:
$C_o=0.09\cdot 10^{-4}\cdot 44,01=3.4\cdot 10^{-4} \frac{g}{L}$