Molar Mass; Converting mass to atoms and viceversa

We can use Avogadro's number as a conversion factor, or ratio, in dimensional analysis problems.

If we are given the number of atoms of an element X, we can convert it into moles by using the relationship

                1 mol X=6.022×10^23 X atoms.

Converting Between Number of Atoms to Moles and Vice Versa

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​Molar mass is defined as the mass of one mole of representative particles of a substance.

By looking at a periodic table, we can conclude that the molar mass of the element lithium is 6.94g, the molar mass of zinc is 65.38g, and the molar mass of gold is 196.97g.​

• Each of these quantities contains 6.022×10^23 atoms of that particular element.

• The units for molar mass are grams per mole or g/mol.

• 1.00 mol of carbon-12 atoms has a mass of 12.0g and contains 6.022×10^23 atoms.

• 1.00 mole of any element has a mass numerically equal to its atomic mass in grams and contains 6.022×10^23 particles.

The mass, in grams, of 1 mole of particles of a substance is now

​Converting Grams to Moles of an Element and Vice Versa

We can also convert back and forth between grams of an element and moles. The conversion factor for this is the molar mass of the substance. The molar mass is the ratio giving the number of grams for each one mole of the substance. This ratio is easily found by referring to the atomic mass of the element using the periodic table. This ratio has units of grams per mole or g/mol.