40. If 12.0 gram of O2 is required to inflate a balloon to a certain size at 27 degrees C, what mass of O2 is required to inflate it to the same size and pressure at 81 deg C?

Answer 1

I would do this the long way.
PV = nRT. We can ignore P and R since they are constants; therefore
V = nT
V = (12.0/32)*300 = about 112 but you do it more accurately.
Then 112/(273+81) = n = about 0.31
and 0.31 x 32 = about 10 g.

The short way is
(12/x) = (354/300)
x = 12 x (300/354) = ?
x =