Question

If the density of nitrogen gas at a certain pressure and temperature is 1.20 g/l, how many moles of nitrogen gas are in 15.0 l

Answer 1

density of nitrogen= 1.20 g/l
no. of grams of nitrogen=m= (1.20g/l)(15.0l)= 18 g
molar mass of nitrogen=M= (14*2)= 28 g/mol

no. of moles of nitrogen=m/M=18/28= 0.643 moles