An unknown gas occupies 14.6 L at STP and has a mass of 19.5 g.
The unknown gas is either methane (CH4), carbon dioxide (CO2), nitrogen monoxide (NO), or sulfur dioxide (SO2). Determine the identity of the unknown gas.
you have 14.6/22.4 = 0.65 moles
So the molar mass of your gas is 19.5g/0.65moles = 29.9 g/mole
That's pretty close to 14+16 = 30, so I'd guess NO