1. Starter
Start aim

3. RAM AND THE MOLE
1.16 calculate relative formula masses (Mr) from relative atomic masses (Ar) 1.17 understand the use of the term mole to represent the amount of substance 1.18 understand the term mole as the Avogadro number of particles (atoms, molecules, formulae, ions or electrons) in a substance 1.19 carry out mole calculations using relative atomic mass (Ar) and relative formula mass (Mr)

4. What is the Mr (Relative Formula Mass) of carbon dioxide?
Formula for carbon CO
dioxide 2
Relative
Mass
Number of
atomic mass
atoms in
Number
Element of
atoms(s) in
compound ( A ) r
compound C 1 12 = 12 x O 2 16 = 32 x 44
Relative Formula
Mass (M ) of r
carbon dioxide ( CO
) is.... 2

5. Calculate the Relative Formula Mass (Mr) of these compounds
H2O
H2SO4
NH3 O2
CaCO3
HNO3
NaCl
Ca(OH)2
MgBr2

6. Calculate the Relative Formula Mass (Mr) of these compounds
(2 x 1) + 16
= 18
40 + (1+16)+(1+16)
= 74
H2O
Ca(OH)2
2 x 16
= 32
14 + (3 x 1)
= 17 O2
NH3
= 58.5
(3x16)
= 63
NaCl
HNO3
(2x1) (4 x 16)
= 98
24 + (2 x 80)
= 184
H2SO4
MgBr2
(3 x 16)
= 100
CaCO3

7. THE MOLE

8. THE MOLE The mole is a chemical mass unit.
1 mole = x 1023 particles
The Mr in grams of any substance contains 1 mole of particles.

9. Just How Big is a Mole?
Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles.
If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.
If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

10. Learning Check 1. How many paper clips in 1 rapp? a) 1 b) 4 c) 8
Suppose we invented a new collection unit called a rapp. One rapp contains 8 objects.
1. How many paper clips in 1 rapp?
a) 1 b) 4 c) 8
2. How many oranges in 2.0 rapp?
a) 4 b) 8 c) 16
3. How many rapps contain 40 gummy bears?
a) 5 b) 10 c) 20

11. The Mole 1 dozen cookies = 12 cookies
1 mole of cookies = 6.02 X 1023 cookies
1 dozen cars = 12 cars
1 mole of cars = 6.02 X 1023 cars
1 dozen Al atoms = 12 Al atoms
1 mole of Al atoms = 6.02 X 1023 atoms
Note that the NUMBER is always the same, but the MASS is very different!
Mole is abbreviated mol

12. How many? 1. Number of atoms in 0.500 mole of Al a) 500 Al atoms
b) x 1023 Al atoms
c) x 1023 Al atoms
2.Number of moles of S in 1.8 x 1024 S atoms
a) mole S atoms
b) mole S atoms
c) x 1048 mole S atoms

14. H2O
CO2
CaCO3
Mr = 18
Mr = 44
Mr = 100
18g
44g
100g
Contains x 1023 particles of H2O
Contains x 1023 particles of CO2
Contains x 1023 particles of CaCO3
The Mr in grams of any substance will contain 1 mole of particles
(i.e. 6 x 1023 particles)

15. Mass, Moles and RAM (Mr)
Mass
Moles
RAM

16. Try these..... = = = 2 moles Calculations with moles Question:
How many moles are there in 32g of CH4?
Q1. How many moles are there in 365g of HCl?
Use the formula:
Q2. How many moles are there in 42.5g of NH3?
Mass (g)
Number
of moles = Mr
Q3. How many moles are there in 285g of MgCl2?
Mr of CH4 is: 12 + (4 x 1) = 16
So,
Q4. How many moles are there in 472.5g of HNO3?
32g
Number
of moles = 16
Q5. How many moles are there in 192.4g of Ca(OH)2?
Number
of moles
= 2 moles

17. Answers... 365g = 10 moles 36.5 42.5g = 2.5moles 17 285g = 3 moles 95
Q1. How many moles are there in 365g of HCl? =
10 moles
36.5
42.5g
Q2. How many moles are there in 42.5g of NH3? =
2.5moles 17
285g
Q3. How many moles are there in 285g of MgCl2? =
3 moles 95
472.5
Q4. How many moles are there in 472.5g of HNO3? =
7.5 moles 63
192.4
Q5. How many moles are there in 192.4g of Ca(OH)2? =
2.6 moles 74

18. Molar Mass 1 H2O 2 CO2 3 NH3 4 C2H5OH 5 C2H4 6 SO2 7 SO3 8 HBr 9 H2SO4
10 HNO3

19. Calculating moles
g of H2O g of CO g of NH g of C2H5OH g of C2H g of SO g of SO g of HBr g of H2SO g of HNO3

20. Calculating mass