1. The Mole
Molar Conversions

2. A. What is the Mole? A large amount!!!! VERY
A counting number (like a dozen)
Avogadro’s number
1 mol = 6.02  1023 particles
(atoms, molecules, or formula units)
A large amount!!!!
VERY

3. B. Molar Mass Mass of 1 mole of an element or compound.
Molar Mass is equal to atomic mass, but the unit for molar mass is grams/mole (g/mol)

4. B. Molar Mass Examples Use 2 Decimal Places carbon 12.01 g/mol
aluminum
zinc
12.01 g/mol
26.98 g/mol
65.39 g/mol

5. B. Molar Mass Examples water H2O 2(1.008) + 16.00 = 18.02 g/mol
sodium chloride
H2O
2(1.008) = g/mol
NaCl
= g/mol

6. B. Molar Mass Examples sodium bicarbonate NaHCO3
sucrose
NaHCO3
(16.00) = g/mol
C12H22O11
12(12.01) + 22(1.01) + 11(16.00) = g/mol

7. (atoms, molecules or formula units)
C. Molar Conversions
1 mole
Molar mass
6.02  1023
1 mole
MASS IN
GRAMS
MOLES
NUMBER OF
PARTICLES
(atoms, molecules or formula units)
Molar mass
1 mole
1 mole
6.02 x 1023

8. C. Molar Conversion Examples
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

9. C. Molar Conversion Examples
How many molecules are in 2.50 moles of C12H22O11?
6.02  1023
molecules
1 mol
2.50 mol
= 1.51  1024
molecules
C12H22O11

10. C. Molar Conversion Examples
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

11. C. Mole Conversion Examples
How many moles are represented by 11.5 g of C2H5OH?
How many molecules is this?
What is the mass of 9.30 moles of SiH4?
Convert 8.00 x 1020 molecules of H2 to moles.

12. Answers
0.25 mole
1.51 x 1023 molecules g
1.33 x 10-3 mole or mole

13. C. Molar Conversion Examples
Find the mass of 1.00 Fe atom
1 mole Fe = 55.85g
1 mole Fe = 6.02 x 1023 atom
1.00 atom Fe g
1 mole
6.02 x 1023 atoms
1 mole
= x g/atom

14. C. Molar Conversions = 9.075 x 1023 atoms
How many Oxygen atoms are there in g of CaCO3?
50.25g CaCO3
6.02 x 1023atoms O
1 mol CaCO3
3 mol O g
1 mol CaCO3
1 mol O
= x 1023 atoms

15. The Mole-Volume Relationship

16. The Volume of a Gas Many of the chemicals we deal with are gases
They are difficult to mass
Two things effect the volume of a gas
Temperature and pressure
We need to compare gases at the same temperature and pressure

17. Standard Temperature and Pressure (STP)
0°C and 1 atmosphere (atm) of pressure
At STP, 1 mole of any gas occupies 22.4 L
Called the molar volume
1 mole = 22.4 L of any gas at STP

18. Practice examples What is the volume of 4.59 mole of CO2 gas at STP?
How many moles is 5.67 L of O2 at STP?
What is the volume of 8.8 g of CH4 gas at STP?

19. Molarity –Molar Volume of… Solutions!
Molarity = moles of solute
liter of solution
M= n V
n = moles of solute
V = volume (L) of solution
Solution = solute + solvent

20. Molarity Examples
How many moles of NaCl are in 0.65 L of 1.20 M NaCl solution?
0.78 moles NaCl
How many moles of HCl are there in 2.43 L of 0.25 M HCl (aq)?
0.61 moles HCl

21. Molarity Examples
How many grams of HF are there in 0.55 L of 1.5 M HF solution?
17 g
How many grams of HNO3 are there in 2.50 L of 5.00 M HNO3 (aq)?
788 g

22. Molarity Examples
Calculate the molarity of a solution made by dissolving 23.4 g of sodium sulfate in 125 ml of solution (hint: you need to find the formula of sodium sulfate)
23.4 g Na2SO4  mol
125 ml  L
M = mol / L
M = 0.165mol / L
1.32 M

23. Molarity Examples
Calculate the molarity of a solution made by dissolving 5.00 g of C6H12O6 in enough water to make ml of solution
0.280 M

24. Molarity Examples
How many grams of Na2SO4 are required to make L of a M solution of Na2SO4?
24.9 g Na2SO4