1) The document discusses moles, Avogadro's number, and molar mass. It defines a mole as 6.02 x 1023 particles, such as atoms, ions, or molecules. 2) To convert between moles and particles, atoms, or molecules, you must multiply or divide by Avogadro's number. Molar mass is the mass in grams of one mole of a substance and is used to convert between moles and grams. 3) Examples are provided for calculating molar mass and for converting between moles, grams, and number of particles using molar mass and Avogadro's number.

1. Moles, Avogadro’s
Number and Molar Mass
Converting moles to molecules,
atoms, and particles

2. Can anyone define the
term mole?

3. a) 1 dozen = 12 units b) 1 pair = 2 units
Daily life – we used:
To delegate a big quantity:
Definition
Chemistry- mole concept:
Mole is a substance quantity that contain a
number of particles such as atom, ion, or
molecule that have equal number of atom in 12
gram of 12C or 6.02 x 1023 particles

4. Example:
1 year = 12 months
1 month = 30 days
1 kg = 1000 g
1 km = 1000 m
1 dozen oxygen atoms = 12 oxygen atoms
1 mole oxygen atoms = 6.02 x 1023 oxygen atoms
1 mole sodium atoms = 6.02 x 1023 sodium atoms
1 mole carbon atoms = 6.02 x 1023 carbon atoms
Daily life
Chemistry

5. Mole
 SI unit used to measure the amount of a
substance
 equal to 6.02 x 1023 atoms, molecules, or
particles
 Avogadro’s number
 Abbreviated by mol

6. Avogadro’s Number
 6.02 X 1023
 Used to count extremely small particles
 Named in honor of Italian physicist
Amedeo Avogardo
 Determined the volume of one mole of a gas

7. Conversions

8. Mole  Molecules, Atoms, or
Particles
 In order to convert moles to molecules
atoms, or particles, you have to
MULTIPLY the number of moles by
Avogadro’s number (6.02 x 1023)
 Example: How many atoms are there in
4.0 moles?

9. How many atoms are there in 4.0
moles?
Moles  Atoms…MULTIPLY BY AVOGADRO’S
NUMBER
2.4 x 1024 atoms

10. Molecules, Atoms, or Particles 
Moles
 In order to convert molecules, atoms, or
particles to moles, you have to DIVIDE
the number of moles by Avogadro’s
number (6.02 x 1023)
 Example: How many moles are there in
7.14 x 1023 molecules?

11. How many moles are there in 7.14
x 1023 molecules?
Molecules  Moles…DIVIDE BY AVOGADRO’S
NUMBER
1.19 moles

12. Practice

13. How many molecules are there in
3.5 moles?
Moles  Molecules…MULTIPLY BY
AVOGADRO’S NUMBER
2.11 x 1024 molecules

14. How many particles are there in 9.6
moles?
Moles  Particles…MULTIPLY BY
AVOGADRO’S NUMBER
5.78 x 1024 particles

15. How many moles are there in 5.75
x 1024 atoms?
Atoms  Moles…DIVIDE BY AVOGADRO’S
NUMBER
9.55 moles

16. How many moles are there in 3.58
x 1023 particles?
Molecules  Moles…DIVIDE BY AVOGADRO’S
NUMBER
0.59 moles

17. Molar Mass

18. Molar Mass
 the mass in grams of one mole of any
pure substance
 In other words, the molar mass of any
element is equivalent to the atomic mass
of that element
 in units of grams per mole; g/mol

19. Calculating Molar Mass
 - To calculate the molar mass of a
substance, you add the atomic mass of
every element in the compound
 The total atomic mass is the molar mass of
the substance.

20. Example
What is the molar mass of N?
Step 1: determine the atomic mass
N: 14
Step 2: add units
g/mol
molar mass = 14 g/mol

21. Example
What is the molar mass of CO2?
Step 1: determine the mass of each element
C: 12
O: 16 X 2
Step 2: add the masses to get the total atomic mass
12+16+16=44
Step 3: add units
g/mol
Molar mass = 44 g/mol

22. Practice
 What is the molar mass of NaCl?
 58.5 g/mol
 What is the molar mass of H3O?
 19 g/mol
 What is the molar mass of H2SO4?
 98 g/mol

23. Mole  Gram
Conversions

24. Review
 Mole
 SI unit used to measure the amount of a substance
 Abbreviate by mol
 Molar mass
 total atomic mass of every element in the compound
 Units: g/mol

25. What is the molar mass of NH3?
 Step 1: determine the mass of each element
 N: 14
 H:1 X 3
 Step 2: total the masses
 14+3=17
 Step 3: attach the units
 17g/mol

26. Mole  Gram Conversions
 When given the number of moles,
MULTIPLY by the molar mass of the
substance.
 What is the mass of 5 moles of H2O?

27. What is the mass of 5.O moles of
H2O?
 Step 1: Write the given
 Step 2: Multiply by molar mass
 Step 3: Cancel the units
 Step 4: Solve
90 grams H2O

28. Gram  Mole Conversions
 When given the number of moles,
DIVIDE by the molar mass of the
substance.
 How many moles are equivalent to 50g N?

29. How many moles are equivalent to
50g N?
 Step 1: Write the given
 Step 2: Divide by the molar mass
 Step 3: Cancel the units
 Step 4: Solve
3.57 moles N

30. Practice

31. What is the mass of …
 2.22 mol Ti
 106 g Ti
 1.22 X 1023 mol Ag
 1.32 X 1025 g Ag
 4.5 mol H2SO4
 441 g H2SO4

32. How many moles are consumed
in…
 5.62 g Kr
 0.0669 mol Kr
 55 g As
 0.73 mol As
 7.5 g NaCl
 0.128 mol NaCl

33. Particles  Gram Conversions
 Remember, particles, atoms, and
molecules are all the same
 To convert particles to grams…
 1st: convert particles to moles
 2nd: convert moles to grams

34. Review
 When converting from moles to atoms,
molecules, or particles, you must
MULTIPLY by Avogadro’s number.
 When converting atoms, particles, or
molecules to moles, you must DIVIDE by
Avogadro’s number.

35. What is the mass of 2.5 X 1023
atoms of H2O?
 Step 1: convert atoms to moles
 Step 2: convert moles to grams

36. Grams  Particles Conversions
 Once again, remember particles, atoms,
and molecules are all the same
 To convert grams to particles…
 1st: grams to moles
 2nd: convert moles to particles

37. How many molecules are in 4.5 g
C?
 Step 1: Convert grams to moles
 Step 2: Convert moles to molecules

38. Practice
 How many grams are in 5.0 X 1024 atoms of K?
 What is the mass of 8.5 X 1023 molecules of
NH2?
 How many particles are in 3.75 g Ca?
 How many molecules are in 96 g HBr2?