Question

Which one of these samples contains the smallest number of molecules?


a.
1.0 L of H2 at STP (0°C and 1atm)
d.
1.0 L of N2 at 0°C and 800 torr
b.
1.0 L of N2 at STP
e.
1.0 L of He at STP
c.
1.0 L of H2 at 20°C and 760 torr

Answer 1

I suppose the simplest thing to do is to calculate the number of mols of each although 1.0 L at STP will give the same number of mols no matter which gas is used.
PV = nRT

You can use reasoning if you wish. Note that n = PV/RT so when T is greater than standard T n will be greater and when P is larger than standard you know n will be larger. I figure the smallest one will be either c or d.

Answer 2

hjojp