1. Stoichiometry: Molar Conversions

2. What is the Mole? A counting number (like a dozen) Avogadro’s number
1 mole = 6.02  1023 items

3. How Much is a Mole?
1 mole of hockey pucks would equal the mass of the moon!
1 mole of basketballs would fill a bag the size of the earth!

4. Molar Mass: the mass of 1 mole of a substance (element or compound)11 Na
Atomic mass tells the:
atomic mass units per atom (amu)
grams per mole (g/mol)
Round to 2 decimal places

5. There are 12 particles in the nucleus of a Carbon atom
There are 12 particles in the nucleus of a Carbon atom. The mass of 1 atom of Carbon = 12 amu The mass of 602,200,000,000,000,000,000,000 atoms of Carbon = 12 grams

6. Molar Mass of Atoms 6.94 g/mol 26.98 g/mol 132.91 g/mol
Lithium Aluminum Cesium
6.94 g/mol
26.98 g/mol
g/mol

7. Molar Mass of Compounds
H2O
2(1.01) = g/mol
NaCl
= g/mol

8. Molar Mass Examples NaHCO3
(16.00) = g/mol
C12H22O11
12(12.01) + 22(1.01) + 11(16.00) = g/mol

9. Molar Conversions molar mass 6.02  1023 (g/mol) (particles/mol) MOLESIN
GRAMS
MOLES
NUMBER OF
PARTICLES
(g/mol)
(particles/mol)

10. When to Use Molar Mass (from chart):
When converting the same substance from
g  mol
mol g
REMEMBER:
Mass Number= number grams in 1 mole of the substance
Can use mol/g or g/mol

11. How many moles of carbon are in 26 g of carbon?
Practice Problem #1
How many moles of carbon are in 26 g of carbon?
26 g C
1 mol C
12.01 g C
= 2.2 mol C

12. How many grams of carbon are in 5moles of carbon?
Practice Problem #2
How many grams of carbon are in 5moles of carbon?
5 mol C
12.01 g C
1mol C
= 60g C

13. How many moles of CO2 are in 26 g of CO2?
Practice Problem #3
How many moles of CO2 are in 26 g of CO2?
26 g CO2
1 mol CO2
44.01 g CO2
=.59 mol CO2

14. How many grams of CO2 are in 3 mol of CO2?
Practice Problem #4
How many grams of CO2 are in 3 mol of CO2?
3 mol CO2
44 g CO2
1 mol CO2
=132 g CO2

15. Molar Conversions molar mass 6.02  1023 (g/mol) (particles/mol) MOLESIN
GRAMS
MOLES
NUMBER OF
PARTICLES
(g/mol)
(particles/mol)

16. When to Use Avogadro's Number:
When converting the same substance from
g  number of particles
number of particles  g
mol number of particles
Number of particles  mol
REMEMBER:
Avogadro's Number = x 1023
Can use mol/particles or particles/mol

17. How many molecules are in 2.50 moles of C12H22O11?
Practice Problem #1
How many molecules are in 2.50 moles of C12H22O11?
6.02  1023
molecules
1 mol
2.50 mol
= 1.51  1024
molecules
C12H22O11

18. Find the mass of 2.1  1024 molecules of NaHCO3.
Practice Problem #2
Find the mass of 2.1  1024 molecules of NaHCO3.
2.1  1024
molecules
1 mol
6.02  1023
molecules
84.01 g
1 mol
= 290 g NaHCO3

19. When to Use Mole Ratio (from equation):
When converting from one substance to another
REMEMBER:
Coefficient tells you the number of moles of each sustance

20. How many moles of O2 can be produced from 12.00 moles of NaClO3?
Practice Problem #1
2NaClO3  2NaCl + 3O2
How many moles of O2 can be produced from moles of NaClO3?
12 mol NaClO3
3 mol O2
2 mol NaClO3
= 18 mol O2

21. How many moles of NaCl can be produced from 10.00 moles of NaClO3?
Practice Problem #2
2NaClO3  2NaCl + 3O2
How many moles of NaCl can be produced from moles of NaClO3?
10 mol NaClO3
2 mol NaCl
2 mol NaClO3
= 10 mol NaCl

22. Practice Problem #3 KOH + HCl KBr + H2O = 21.21 g KBr 10 g KOH
If you start with 10 grams of potassium hydroxide, how many grams of potassium bromide can be made?
Molar Mass
Mole Ratio
Molar Mass
10 g KOH
1 mol KOH
56.11 g KOH
1 mol KBr
1 mol KOH
119 g KBr
1 mol KBr
= g KBr

23. Practice Problem #4 Si2H4 + 3O2 2SiO2+ 2H2O = 89.81g SiO2 45 g Si2H4
If you start with 45 grams of Si2H4, how many grams of SiO2 can be made?
45 g Si2H4
1 mol Si2H4
60.22 g Si2H4
2 mol SiO2
1 mol Si2H4
60.09g SiO2
1 mol SiO2
= 89.81g SiO2