5 liters of O2 at 300K and 400 torr what will it weigh in grams?

Answer 1

I don't have my thermodynamic book with me so I solve this question with a little assumption, you can check it with the exact conversions. I show you the way, you should pass it yourself if you want to succeed. I teach you how to fish, I won't give you the fish.
assumption (you should check it yourself honey):
1 torr = 1 bar = 10^5 pa
We assume O2 as an ideal gas, so we have:
PV=nRT
in which:
P=pressure
V=volume
n= numbers of moles
R= gas constant= 8.314 (Pa)(m^3) / (K)(mol)
T= temperature
we put the given datas in the above formula and calculate 'n' for O2 under these conditions...
*** Notice: remember that the units must be the same...
n=PV/RT
n= (400*10^5 Pa)(0.005 m^3)/(300 k)(8.314)
n=80.186 mole
1 mole O2 = 32 gr
gr O2 = 80.186*32 = 2565.95 gr
Good Luck...

Answer 2

Two solutions:

1.) Use PV = nRT. In this case, R = 6.23 x 10^4 mL-torr/mol-K
Solve for number of moles, n. One mole CO2 = 44g

2.) Convert to standard temperature anbd pressure, where you know that one mole is 22.4L

5LCO2 x 273K/300K x 400torr/760torr x 1molCO2/22.4LCO2 x 44gCO2/1molCO2 = (5)(273)(400)(44)/(300)(760)(22.4) = 4.7gCO2