Today in class, we learned how to figure out the density of Gases at STP. It's really simple, the standard formula in getting the density of an object is:

D= M/V (Wherein D= Density, M= Molar Mass and V= Volume)

As you can see, the units of the Molar Mass and the Volume of the object will cancel out and will end up to g/L which will be the unit for Density.

The Density of Gases at STP will always have a volume of 22.4L, while it's molar mass depends on the chemical formula of the gas- which we can also figure out by just looking at the periodic table.

Also, we learned today that not only can we figure out the density of the gas with the formula D=M/V, but also we can figure out either the molar mass or the volume of the object- depending of course with what is given.

M=(D)(V) or V= M/D