1. Molecular Mass

2. Elements Single elements by themselves 1 mole = 6 x 1023 atoms
Example: Sodium Na
1 mole = 6 x 1023 atoms
1 mole Na = 6 x 1023 atoms of Na
1 mole = atomic weight in grams
1 mole Na = 23 grams Na

3. Compounds More than one element chemically combined
Example: Na2(SO4)
1 mole = 6 x 1023 molecules
1 mole Na2SO4 = 6 x 1023 molecules Na2SO4
1 mole = molecular weight in grams
1 mole Na2SO4 = (2x23) + (1x32) + (4x16)
= 142 grams

4. Dimensional Analysis
If you had 5 grams of Na, how many moles do you have?
Identify what is given to you.
- 5 grams Na
Identify what you are trying to find.
- moles of Na

5. Dimensional Analysis
If you had 5 grams of Na, how many moles do you have?
3. Identify the correct conversion factor.
1 mole of Na, =23 grams, therefore
1 mole Na OR grams
23 grams mole Na

6. Dimensional Analysis
If you had 5 grams of Na, how many moles do you have?
Calculate the answer.
5 grams Na 1 mole Na = moles Na
23 grams Na

7. Dimensional Analysis
If you had 5 grams of Na2SO4, how many moles do you have?
Identify what is given to you.
- 5 grams Na2SO4
Identify what you are trying to find.
- moles of Na2SO4,

8. Dimensional Analysis
If you had 5 grams of Na2SO4, how many moles do you have?
3. Identify the correct conversion factor.
1 mole of Na2SO4, =142 grams, therefore
1 mole Na2SO4, OR grams
142 grams mole Na2SO4,

9. Dimensional Analysis
If you had 5 grams of Na2SO4, how many moles do you have?
Calculate the answer.
5 grams Na2SO mole Na2SO4, = mol Na2SO4
142 grams Na2SO4