Molar mass is found by adding together the masses found on the periodic table!
Example: Find the molar mass of aluminum chloride
- Aluminum chloride has a formula of AlCl3
- That means you have one aluminum and 3 chlorines
- So....
26.9815 + (3 * 35.453) = 133.34 g/mol
Example: Find the molar mass of ammonium sulfide
- ammonium sulfide has a formula of (NH4)2S
- The 2 outside of the ( ) means you have to distribute the 2 so you have 2 nitrogens, 8 hydrogens, and 1 sulfide
- So....
(2 * 14.0067) + (8 * 1.00794) + 32.066 = 68.14 g/mol
You Try!
Find the molar mass of the following compounds:
1) iron (III) sulfide
2) Magnesium bromide
3) aluminum hypochlorite
Answers:
1) Formula: Fe2S3 molar mass: 207. 89 g/mol
2) Formula: MgBr2 molar mass: 184.11 g/mol
3) Formula: Al(ClO)3 molar mass: 181.34 g/mol
- Aluminum chloride has a formula of AlCl3
- That means you have one aluminum and 3 chlorines
- So....
26.9815 + (3 * 35.453) = 133.34 g/mol
Example: Find the molar mass of ammonium sulfide
- ammonium sulfide has a formula of (NH4)2S
- The 2 outside of the ( ) means you have to distribute the 2 so you have 2 nitrogens, 8 hydrogens, and 1 sulfide
- So....
(2 * 14.0067) + (8 * 1.00794) + 32.066 = 68.14 g/mol
You Try!
Find the molar mass of the following compounds:
1) iron (III) sulfide
2) Magnesium bromide
3) aluminum hypochlorite
Answers:
1) Formula: Fe2S3 molar mass: 207. 89 g/mol
2) Formula: MgBr2 molar mass: 184.11 g/mol
3) Formula: Al(ClO)3 molar mass: 181.34 g/mol