Question

Laughing gas is a compound called dinitrogen
monoxide. what amount (in mol) of dinitrogen
monoxide, n2o(g), contains 3.40 x 10^23 molecules?

Answer 1

This is stoichiometry.

1 mole
3.40 x 10^23 molec. • ———
6.02 x 10^23 molec.

Multiply everything on top and divide by everything multiplied on bottom.