Methane is formed in landfills by the action of certain bacteria on buried organic matter. If a sample of methane collected from a landfill has a volume of 200. mL at 741 torr and 27.2 °C, how many grams of methane are in the sample?
Use PV = nRT and solve for n = number of mols CH4. Then n = grams/molar mass. You have molar mass and n, solve for grams.
What would my R be?
741torr x 200mL=nR X 27.2
If P is changed to atm [(741/760) = ?] then R is 0.08205 L*atm/mol*K
so
.975 x 200mL = n x .08205 x 27.2?
P in atm (741/760) = ? atm
V in L. 200 mL = 0.200 L
T in kelvin. K = 273 + 27.2 = ?
With all of those, R = 0.08205.
so could I solve like n=.975atm *.200L * (300.2/.08205)? 713.45
and thank you for your help!
Since they threw that T as 27.2 then I would add to 273.2 to convert to K (I missed that above) so I would use 300.4 and not 300.2. That gives you n = number of mols. The problem asks for grams methane. g methane = mols x molar mass CH4 = mols methane x 16 = ?
Note: Check your math on the calculator. I don't get 713 but more like 0.0079something. I think you MULTIPLIED the 300.2 and didn't divide. You just hit the x button instead of the divide button.