Grade 11 Physical Science Mole Notes.ppt

1. What’s up with
the Mole?

2. How do we measure matter?
By weight:
We buy bananas by the _______________.
By volume:
Milk is sold by the ____________________.
By counting:
There are ________ students in class.
kilo
ml

3. Chemical Quantities
Many words are used to express a specific quantity.
 Pair =
 Dozen =
2
12

4. How do we measure matter?
• What if I wanted to know how many ATOMS
were in this copper penny? Would you like
to count? Could you?

5. Avogadro’s Number
• You can count particles if you introduce a term
that represents a specified number of particles.
• In chemistry, the term used to express a specific
number of particles is a mole.

6. Avogadro’s Number
• 1 mole = 6.02 x 1023
particles
• That’s 602,000,000,000,000,000,000,000
602,000,000,000,000,000,000,000
• A very large number!

7. Avogadro’s Number
This number is known as
Avogadro’s number, named after
Amedeo Avogadro (an Italian
physicist and mathematician).

8. Representative Particles
Representative particles are units used to measure the
number of particles in a sample of an element or
compound.
Substance Representative Particle
element atom
covalent compound molecule
ionic compound formula unit

9. Representative Particles
What is the representative particle for each of these substances?
•copper
•sodium chloride
•water
atom
molecule
formula unit

10. MOLE
• Use dimensional analysis to convert:
– moles to molecules
– moles to atoms
– moles to formula units
– moles to grams
– grams to atoms
– and many more….

11. MOLE
When converting between moles and particles,
the conversion factor to remember is:
1 mol = 6.02 x 1023
particles
The particle unit can be atoms, molecules, or
formula units.

12. Mole/Particle Examples
1. How many moles are in 3.25 X 1020
atoms of lead?
3.25 x 1020
atoms Pb
1 mol = 6.02 x 1023
atoms
6.02 x 1023
atoms Pb
1 mol Pb
= 5.398671 x 10-4
= 5.40 x 10-4
mol Pb

13. Mole/Particle Examples
2. How many molecules are there in 8.3 moles of sugar
(C12H22O11)?
8.3 mol C12H22O11
1 mol = 6.02 x 1023
molecules
6.02 x 1023
molec. C12H22O11
1 mol C12H22O11
= 5.0 x 1024
molec. C12H22O11
= 4.9966 x 1024

14. Mole/Particle Examples
3. How many atoms are in 0.425 mol sulfur?
0.425 mol S
1 mol = 6.02 x 1023
atoms
6.02 x 1023
atoms S
1 mol S
= 2.56 x 1023
atoms of S
= 2.5585 x 1023

15. Mole/Particle Examples
4. How many moles are in 5.42 x 1022
formula units of NaCl?
5.42 x 1022
Form. U NaCl
1 mol = 6.02 x 1023
Formula Unit
6.02 x 1023
Form. U NaCl
1 mol NaCl
= 0.090033222 = 0.0900 mol NaCl

16. Molar Mass
molar mass – the mass in grams of one mole of an element or
compound.

17. Terms that Describe the Mass of a Substance
• Atomic mass – mass of one atom of an element
(unit = amu)
• Molecular mass - mass of one molecule of a
covalent compound (unit = amu)
• Formula mass - mass of one formula unit of an
ionic compound (unit = amu)
• Molar mass - mass of one mole of an element or
compound (unit = g/mol).

18. Molar Mass
To calculate molar mass:
1. Obtain all of the masses of the involved
elements from the periodic table.
2. Multiply each element’s mass by the subscript.
3. Add the resulting products.
4. Round the answer to the proper number of
decimal places.

19. Molar Mass of Element Examples
• Aluminum =
• Zinc =
26.982 = 26.98 g/mol
65.38 g/mol

20. Molar Mass of Compounds Examples
• Diphosphorus pentaoxide P2O5
P =
O =
30.974
15.999
X 2
X 5
= 61.948
= 79.995 +
141.943 = 141.94 g/mol

21. Molar Mass of Compounds Examples
• Aluminum Hydroxide Al(OH)3
Al =
O =
26.982
15.999
X 1
X 3
= 26.982
= 47.997
+
78.003 = 78.00 g/mol
H = 1.008 X 3 = 3.024
+3 -1

22. Molar Mass of Compounds
Examples
• Barium phosphate Ba3(PO4)2
Ba =
P =
137.328
30.974
X 3
X 2
= 411.984
= 61.948
+
601.924 = 601.92 g/mol
O = 15.999 X 8 = 127.992
+2 -3

23. Moles to Mass
• Use dimensional analysis to convert
–moles to mass or mass to moles.
• Mass unit = grams
• Conversion Factor to Remember:
– 1 mol = molar mass of the element or compound
(molar mass = g/mol) found on the periodic table

24. Moles to Mass Examples
• How many moles of carbon are in 26 g of
carbon?
26 g of C
Carbon: 1 mol = 12.01 g (from PT)
1 mol of C
12.01 g of C
= 2.2 mol of C
= 2.164862614

25. Moles to Mass Examples
• How many grams are there in 2.37 moles of
CO2?
2.37 mol CO2
C = 12.011 x 1
O = 15.999 x 2
44.01 g CO2
1 mol CO2
= 104 g CO2
= 104.3037
= 12.011
= 31.998+
44.009 g = 1 mol

26. Moles to Mass Examples
• How many moles are present in 142.1
grams of NaCl?
142.1 g NaCl
Na = 22.990 x 1
Cl = 35.453 x 1
1 mol NaCl
58.44 g NaCl
= 2.432 mol NaCl
= 2.43155373
= 22.990
= 35.453+
58.443 g = 1 mol

27. Moles to Mass Examples
• How many grams are in 3.34 moles of
potassium bromide?
3.34 mol KBr
K = 39.098 x 1
Br = 79.904 x 1
119.00 g KBr
1 mol KBr
= 397 g KBr
= 397.46
= 39.098
= 79.904+
119.002 g = 1 mol
+1 -1
KBr

28. Molar Volume of a Gas
• The volume of a gas changes as the
temperature and pressure change, so the
volume is usually measured at standard
temperature and pressure.
• STP = abbreviation for standard temperature
and pressure
• Standard temperature = 0o
C = 273 K
• Standard pressure = 1 atm or 101.3 kPa

29. Molar Volume of a Gas
• At STP, one mole of any gas occupies the same
volume: 22.4 L.

30. Molar Volume of a Gas
• Use dimensional analysis to convert:
–volume (liters) to moles
–or moles to volume (liters)
• Conversion Factor to Remember:
–1 mole = 22.4 L

31. Molar Volume of a Gas
Examples
• Determine the volume, in liters, of 0.60 mol
SO2 gas at STP.

32. Molar Volume of a Gas
Examples
• Assuming STP, how many moles are in 67.2 L
SO2?

33. Molar Volume of a Gas
Examples
• How many moles are in 1.0 x 103
L of C2H6?

34. Molar Volume of a Gas
Examples
• What is the volume at STP of 3.20 x10-3
mol
CO2?

35. Mole Calculations Learned
MOLES
# of Particles
(atoms,
molecules,
formula units)
Mass
(grams)
Liters of gas
at STP
1 mol =
6.02 x 1023
particles
1 mol = 22.4 L
1 mol = mass from
Periodic Table

36. Problem 1
1 mol = 6.02 x 1023
atoms

37. Problem 2
1 mol = 6.02 x 1023
molecules

38. Problem 3
1 mol = 6.02 x 1023
Formula Unit

39. Molar Mass of Compounds
4. Calculate the molar mass of C₆H₁₂O₆
(glucose).
5. Calculate the molar mass of Al₂(SO₄)₃
(aluminum sulfate).