C, a compound because it means it was made up of more than one element but, still able to be separated from the other compound(s)
Standard temperature is 273 K
Standard pressure is 1 atm
We use the ideal gas equation to find out density of nitrogen gas in g/L
Ideal gas equation:
Molar mass of
Pressure = 1 atm
Temperature = 273 K
= 1.25 g/L
Therefore, density of nitrogen gas at STP is 1.25 g/L