# How do I calculate the mass in grams for each of the following?

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Hi! I need to calculate the mass in grams of each of the following: 6.03×10^20 H2O2 molecules, 6.0×1025 O3 molecules, and 9.88×1019 CH4 molecules. If someone could explain to me how to do this it would be greatly appreciated. Thank you in advance!

Hi! I need to calculate the mass in grams of each of the following: 6.03×10^20 H2O2 molecules, 6.0×1025 O3 molecules, and 9.88×1019 CH4 molecules. If someone could explain to me how to do this it would be greatly appreciated. Thank you in advance!

##### 1 Answer

I'll go through it below.

#### Explanation:

Let's start with the mole and avagadro's number. Simplistically, the mole is a simple way to count LOTS and LOTS of "particles" (atoms, molecules, ions, compounds...whatever).

We can go back to carbon and say; "Right, so if you take 12.0 grams of Carbon-12 (the isotope), then you've got 1 mole of carbon, and that is

So, 1 mole of anything is

And on the periodic table, the mass of

Anyway, from molecules - to moles - to atoms.

It is the exact same setup for the others - but with different molar masses and different numbers of molecules to start.