1. Starter S-93 What is the molar mass of H2S?
How many moles of H2S would be found in 100 g?
How many formula units (particles) of H2S would be in 100g?

2. Chapter 10
Chemical Quantities

3. 10.1 The Mole: A Measurement of Matter
Chapter 10
10.1 The Mole: A Measurement of Matter

4. 10.1 The Mole Quantitative – yield a number value Most common methods
count
mass
volume

5. 10.1 The Mole
Words often mean a quantity
pair – 2
dozen – 12
mole?

6. 10.1 The Mole
10.1 The Mole
Mole – means a specific number of particles
This is called Avogadro’s Number
The unit is used for
atoms
molecules (covalent compounds)
formula units (ionic compounds)

7. 10.1 The Mole
10.1 The Mole
To convert numbers of particles to moles we need an equality
This could also be Or
Depending on what type of particle you are trying to convert

8. 10.1 The Mole
10.1 The Mole
The rest is just the conversion we have always done
remember – the unit you have goes on the bottom of the fraction
-the unit you are converting to goes on the top
So to convert 2500 atom of C to moles

9. 10.1 The Mole
10.1 The Mole
Converting from moles to partciles follows the same process
How many molecules of Carbon Dioxide are in 1.55 mol?

10. 10.1 The Mole 10.1 The Mole Convert the following quantities to moles
1. 9,487,212 formula units of AgNO3
x1023 atoms of Nitrogen
x1024 molecules of Carbon Monoxide

11. 10.1 The Mole
10.1 The Mole
Convert the following to the correct type of particle
moles of CCl4
x10-3 moles of CuCO3
moles of Helium

12. 10.1 The Mole
10.1 The Mole
By definition, the atomic mass of an element in grams is the mass of one mole of the element.
This is called the molar mass

13. 10.1 The Mole
10.1 The Mole
For a compound we must calculate the molar mass
Write down what type of atoms, and how many of each are present
C 1
H 4
2. Multiply by the molar mass of each element
CH4

14. 10.1 The Mole
10.1 The Mole
For a compound we must calculate the molar mass
Write down what type of atoms, and how many of each are present
C 1 x g =
H 4 x g =
2. Multiply by the molar mass of each element
CH4

15. 10.1 The Mole
10.1 The Mole
For a compound we must calculate the molar mass
Write down what type of atoms, and how many of each are present
C 1 x g = g
H 4 x g = g
Multiply by the molar mass of each element
Add to get a total
CH4

16. 10.1 The Mole
10.1 The Mole
For a compound we must calculate the molar mass
Write down what type of atoms, and how many of each are present
C 1 x g = g unit
H 4 x g = g
Multiply by the molar mass of each element
Add to get a total g CH4
CH4

17. Starter S-94 What is the molar mass of CO?
How many moles of CO would be found in 0.56 g?
How many molecules of CO would be found in 3.51 moles?

18. 10.2 Mole-Mass and Mole-Volume
Chapter 10
10.2 Mole-Mass and Mole-Volume

19. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
We don’t convert from particles to moles nearly as often as we do from moles to grams.
The reason is that we usually measure the amount of a substance on the balance
We need to know numbers of
particles so that we can
compare ratios of atom or
compounds

20. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
This is just another conversion problem
The equality is
Again, the quantity you have goes on the bottom, the quantity you want goes on top
So if you have 9.5g of Carbon
Value Molar Mass = 1 mole

21. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
If you have 2.2 moles of Silver Nitrate convert to mass
First we need to know the formula of Silver Nitrate
Then the molar mass
And finally we can convert

22. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
Try the following example: How many moles is 8.2g of Copper (II) Chloride
Formula
Molar mass
Moles

23. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
And another one: How many grams is 2.4 mol of Iron (III) Sulfate
Formula
Molar mass
Moles

24. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
In 1811, Amedeo Avogadro proposed
Avagador’s Hypothesis – equal volumes of gases at the same temperature and pressure contain equal numbers of particles

25. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
Standard Temperature and Pressure (STP)
T – 0oC or 273K
P – kPa, or 1 atm
At STP the volume of one mole is 22.4L
So the equality for conversion is

26. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
To do these problems, the identity of the gas doesn’t really matter.
If we have 15 L of Chlorine gas
The number of moles would be

27. 10.2 Mole-Mass and Mole-Volume
10.1 The Mole
10.2 Mole-Mass and Mole-Volume
If instead we calculate for a more complicated gas such as propane
And we also have 15 L of propane gas
The number of moles would be

28. Starter S-95 What is the molar mass of Pb(SO4)2?
How many moles of Pb(SO4)2 would be found in 250 g?
How many moles of H2 gas are found in 250 L?

29. 10.3 Percent Composition and Chemical Formulas
Chapter 10
10.3 Percent Composition and Chemical Formulas

30. 10.1 The Mole 10.3 Percent Composition
The relative amounts of the elements in a compound is called the percent composition
The percent by mass of an
element is the number of
grams of the element
divided by the mass in
grams of the compound multiplied by 100%

31. 10.1 The Mole 10.3 Percent Composition
Calculating the mass percent from a formula
Formula
Calculate the total
mass of each element
mass of
the compound
Calculate the
percent by
mass for
each element

32. 10.1 The Mole 10.3 Percent Composition Calculate the mass percent
Formula
Mass of each element
Total mass
Mass Percent

33. Starter S-98
What is the percent by mass of the all the elements in Cu(NO3)2.

34. 10.1 The Mole 10.3 Percent Composition
Empirical Formula – smallest whole number ratio of the elements in a
compound
The empirical formula
can be calculated
from the percent
composition
Compound
Empirical Formula
H2O
CH3COOH
CH2O
C6H12O6 S8 S

35. 10.1 The Mole 10.3 Percent Composition
To calculate the empirical formula
List the elements and their
percent compositions
Convert the percent
compositions to moles
Calculate the mole ratio (divide
by the smallest number of moles)
Smallest Whole Number ratio
Write the Formula

36. 10.1 The Mole 10.3 Percent Composition
To calculate the empirical formula
Elements
Convert to Moles
Mole ratio
Whole Number ratio
Write the Formula

37. Starter S-99 What is the empirical formula if Lead is 59.7%
Hydrogen is 2.9%
Arsenic is 21.6%
Oxygen is 18.4%

38. 10.1 The Mole 10.3 Percent Composition
The molecular formula can be calculated from the empirical formula and the molar mass
Comparison of Empirical and Molecular Formulas
Formula
Classification
Molar Mass CH
Empirical 13
C2H2
Molecular
26 (2x13)
C6H6
78 (6x13)
CH2O 30
C2H4O2
60 (2x30)
C6H12O6
180 (6x30)

39. 10.1 The Mole 10.3 Percent Composition
Steps in calculations (if mass=60.0g)
Determine the empirical formula
Calculate the mass
of the empirical formula
Divide the actual molar mass by
this number
4. Multiply the empirical formula

40. Starter S-102 What is the empirical formula if Silver – 63.5%
Nitrogen – 8.2 %
Oxygen – 28.2%
If the formula mass is 170g, what is the formula of this compound?

41. Starter S-103 What is the empirical formula if Carbon – 49.5%
Hydrogen – 5.2%
Nitrogen – 28.9%
Oxygen – 16.5%
What if the molecular formula, if the molar mass is 194g?