 # I can calculate the molar mass of a compound Sometimes the molar mass is called the formula mass!

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I can calculate the molar mass of a compound Sometimes the molar mass is called the formula mass!

1. Each atom has a unique mass Average atomic mass The mass of a single atom is expressed in atomic mass units, AMU Carbon has an average atomic mass of 12.01 amu

The mole 1 mole= 6.02 x 10 23 particles = average atomic mass expressed in grams analogy- 1 dozen= 12 eggs 6.02 x 10 23 is called AVOGADRO’S number. Example: How many atoms are in 1 mole of helium? 6.02 x 10 23 atoms! How many atoms are in 1 mole of lithium? 6.02 x 10 23 atoms! How many atoms are in 1 mole of nitrogen? 6.02 x 10 23 atoms!

2. The masses are different for atoms of different elements The mass of 1 mole of particles is called the molar mass. Molar mass of an element = average atomic mass expressed in grams/mole What is the molar mass of carbon? What is the molar mass of oxygen?

3. A molecule’s mass depends on the chemical formula and the molar mass of its individual atoms The molar mass of a compound is the mass of one mole of its molecules. Molar mass and formula mass are the same thing! Use chemical formula to calculate molar mass of a compound: Example: H 2 Example CO 2

Molar mass/formula mass H 2 CO 3 Ca(NO 3 ) 2

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