Question

I have a question on my Chem homework. It's asking "How many molecules of N2O4 are in 76.3 g N2O4? The molar mass of N2O4 is 92.02 g/mol." I am really confused as to how to do this. Help??

Answer 1

Here, Molar mass of N2O4 = 92.02 g/mol
So, Number of molecules in 1 mole (92.02 g) = 6.023 * 10²³
Number of molecules in 76.3 g = 6.023 * 10²³ / 92.02  * 76.3
= 6.023 * 10²³ / 1.20
= 5 * 10²³ 

In short, Your Answer would be approx. 5 * 10²³ molecules

Hope this helps!