Molar Mass

How can I find the molar mass of an element?

The molar mass of elements is found by looking at the atomic mass of the element on the periodic table. For example, if you want to find the molar mass of carbon, you would find the atomic mass of carbon on the periodic table, and this is equal to the molar mass in grams per mole. So, in our example, carbon has a molar mass of 12.01 grams per mole.

How can I find the molar mass of a chemical compound?

For any chemical compound that's not an element, we need to find the molar mass from the chemical formula. To do this, we need to remember a few rules:

1. Molar masses of chemical compounds are equal to the sums of the molar masses of all the atoms in one molecule of that compound. If we have a chemical compound like NaCl, the molar mass will be equal to the molar mass of one atom of sodium plus the molar mass of one atom of chlorine. If we write this as a calculation, it looks like this: (1 atom x 23 grams/mole Na) + (1 atom x 35.5 grams/mole Cl) = 58.5 grams/mole NaCl

2. If you have a subscript in a chemical formula, then you multiply the number of atoms of anything next to that subscript by the number of the subscript. For most compounds, this is easy. For example, FeCl2, you have one atom of iron and two atoms of chlorine. The molar mass will be equal to (1 atom x 56 grams/mole Fe) + (2 atoms x 35.5 grams/mole of chlorine) = 127 grams/mole of FeCl2,

Molar mass

Calculate the molar mass of the following compounds1. LiOH 6. C6H12O6

2. Ba(CN)2 7. N2

3. H2O 8. Fe2O3

4. CuSO4 9. Mg(OH)2

5. CO2 10. H2S