How do I use the ideal gas relationship to determine the experimental volume of CO2 at STP?

Question

Average volume of CO₂ in the experiment was 37.68mL.

water temp 20.08 C

vapour pressure of water 17.7 mmHg

Barometric pressure 758.3mmHg

 

P₁V₁/T₁  = P₂V₂/T₂

 

I know I have to rearrange the equation to obtain volume but I'm not sure which values would be input for the variables with subscript 1 and 2. Am I looking for V₂? And if so then the variable with the subscript 1 would be where I input the STP values?

 

 

 

Answer 1

Not exactly sure what the lab experiment was, but seems like it was collecting CO2 gas over water. This being th case, you must subtract the vapor pressure of water from the total pressure to get the pressure of the CO2. 

P1= 758.3 - 17.7 = 740.6 mm Hg

V1 = 0.03768 L

T1 = 293.23 K

P2 = 760 mm Hg

V2 = ?

T2 = 273.15 K

plug and chug to get the answer