We are asked which of the following gases will have the highest volume.
Recall the ideal gas law:
P = pressure, atm
V = volume, L
n = moles, mol
R = gas constant = 0.08206 (L·atm)/(mol·K)
T = temperature, K
We can see here that when P and T are constant, the moles (n) is just directly proportional to Volume (V).
This means we need to identify which has the highest moles.
Now since the mass is also constant and based on the formula for molar mass:
We can say that the lower the molar mass, the higher the number of moles.
Which of the following will have the greatest volume at STP?
(a) 5.0 g H2
(b) 5.0 g N2
(c) 5.0 g O2
(d) 5.0 g CO
(e) all of the above have the same volume