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. 

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 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.


Now we need to convert it to g/L. One mol of CO2 is 44.01g. 
The final answer is:
 

What? i don’t understand