Question

How many molecules are in 79g of fe2o3

Answer 1

Convert grams —> mols and then mols —> atoms

We know that there are 6.02 x 10^23 atoms/mol

And we know that there are about 160 grams of fe2o3 per mol

So (79g fe2o3)/(160 g/mol) = .49 mol fe2o3

Now we use avogadro’s number to do

(.49 mol fe2o3)/(6.02 x 10^23 atoms/mol) = the answer.

I’ll leave the easy math to you.