Periodic molar mass table how to#

How many moles are in 713 grams of Al 2(SO 4) 3? We earlier calculated the molar mass of Fe 2O 3 to be 159.70 g/mol.ģ.81 mol Fe 2O 3 x 159.70 g/1 mol Fe 2O 3 = 608 gĤ. What is the mass in grams of 3.81 moles of Fe 2O 3?

Periodic molar mass table how to#

The following two example problems will illustrate how to use molar mass as a conversion factor between moles and mass. This allows us to convert between grams of Al 2(SO 4) 3 and moles of Al 2(SO 4) 3. Just like there are 12 inches/1 foot, for Al 2(SO 4) 3 there are 342.17 g/mol. This looks a lot like a conversion factor that relates two units: grams to moles. Notice that the units on molar mass are grams per mole (g/mol). There are 5 Mn atoms (mass of 54.94) and 16 O atoms (mass of 16.00). Or Avogadro’s number, 6.022×10 23, of Fe 2O 3 formula units (ionic compound particles) would have a mass of 159.70 g. So one mole of Fe 2O 3 would have a mass of 159.70 g. To calculate its molar mass we have to add up the mass of two iron atoms and three oxygen atoms. To find the mass of one mole of any substance we count the elements present and add up their atomic masses.įor example, let’s calculate the molar mass of iron(III) oxide, Fe 2O 3. Fe 2O 3 is composed of two iron atoms and three oxygen atoms.

So one mole of hydrogen, or 6.022×10 23 hydrogen atoms, has a mass of 1.01 g. Remember that one mole is equal to Avogardo’s number, 6.022×10 23 particles. But one incredibly handy aspect of the periodic table is that those same masses are also the mass of one mole of the element in grams.įor example, one atom of hydrogen has a mass of 1.01 amu, but one mole of hydrogen has a mass of 1.01 g. For example, the atomic mass of hydrogen (symbol H) is 1.01 amu (atomic mass units).

We saw in a previous lesson on atomic mass that the periodic table provides us with the average atomic mass of elements. Molar mass is literally the mass of one mole of a substance.