Problem: How many molecules of nitrogen monoxide are in a 22.5 gram sample?

We are asked to find the number of molecules of nitrogen monoxide (NO) that are in a 22.5-gram sample.

1. Compute for the number of moles NO:

To find the number of molecules of nitrogen monoxide (NO) that are in a 22.5-gram sample, recall the formula for Molar mass;

$\boxed{\mathbf{Molar}\mathbf{ }\mathbf{mass}\mathbf{ }\mathbf{NO}\mathbf{ }\mathbf{=}\frac{\mathbf{ }\mathbf{mass}\mathbf{ }\mathbf{of}\mathbf{ }\mathbf{NO}}{\mathbf{moles}\mathbf{ }\mathbf{NO}}\mathbf{ }}$