Calculate the formula mass of each compound. Keep at least one decimal place in atomic masses from the periodic table.

Question

hydrogen peroxide, H₂O_2:

phosphoric acid, H₃PO_4:

Answer 1

The mass is found on the periodic table for each element and is grams per mole.

So just add the numbers for each atom.

hydrogen peroxide, H₂O_2:

H has a mass of 1.008 and there are 2 of them.

O has a mass of 16.00 and there are 2 of them.

1.008 + 1.008 + 16.00 + 16.00 = 34.016 g/mol or 34.0g/mol if you only use one decimal place.

phosphoric acid, H₃PO_4:

3 hydrogens

1 phophorus

4 oxygens

Just look up the masses on the periodic table and add them and record it as grams/mole