MOLAR MASS

What is Molar Mass

The SUM of the atomic masses of the atomic species as given in the molecular formula.

2 x 35.45 g= 70.90 g/ mole Cl2

Cl2

Atomic mass from periodic table (Rounded to nearest hundredth)

Example 1: Molar Mass of H2O Given is H2O

Step 1:

H: 2 x 1.01= 2.02 g/mol O: 1 x 16.00 = 16.00 g/mol

Step 2:

Add 2.02 g/mol + 16.00 g/mol= All answers MUST be rounded to nearest

hundredth!!

ANSWER

18.02 g/mol H2O

Example2: Molar Mass of Calcium Hydroxide Given is Calcium Hydroxide = Ca(OH)2

Step 1: Ca: 1 x 40.08= 40.08 g/ mol O: 2 x 16.00 = 32.00 g/mol H: 2 x 1.01 = 2.02 g/mol

Step 2: Add 40.08 + 32.00 + 2.02 = All answers MUST be rounded to nearest

hundredth!!

74.10 g/mol Ca(OH)2

ANSWER

Practice: Find the molar mass for each of the following

All answers MUST be rounded to nearest hundredth!!

1.) Sodium Hydroxide: NaOH 2.) Magnesium Chloride: MgCl2 3.) Cu(NO3)2

4.) HNO3

5.) Carbon Dioxide: For # 5 you must provide the formula to

calculate the molar mass