How many molecules are in 0.25 grams of dinitrogen pentoxide?

In order to get the answer, you have to know the formula of how to convert grams to mole and by that you can get the number of molecules.

The answer is 2 moles of N2O5. This is shown by the solution:

(0.25 g N2O5) (1 mol / 108 g) = 2.31 molecules

The answer is 2 molecules.