Question

Oxides of nitrogen are pollutant gases which are emitted from car exhausts.

In urban traffic, when a car travels one kilometre, it releases 0.23 g of an oxide of nitrogen NxOy, which occupies 120 cm3.

What are the values of x and y?
(Assume 1 mol of gas molecules occupies 24.0 dm3.)

A x = 1, y = 1

B x = 1, y = 2

C x = 2, y = 1

D x = 2, y = 4

the ans. is B.. can somebody explain the working?

Answer 1

its easy you need to calculate molar mass of that compound NxOy by next steps:
n=V/Vm = 0,12 dm3/24 dm3mol-1 = 0,005 moles
n=m/M => M=m/n = 0,23g/0,005mol = 46 gmol-1
and now you see that only posibility is NO2 :D

Answer 2

thnx