1. The Mole

2. *Particles can be atoms, molecules, ions, or formula units.
The Mole
The mole (mol) is the SI unit of measure for an amount of a chemical substance.
A mole is equal to Avogadro’s number of particles, that is 6.02 × 1023 particles. Therefore;
1 mol = Avogadro’s Number = 6.02 × 1023 units
We can use the mole relationship to convert between the number of particles, the mass, and number of moles of a substance.
Remember these relationships:
1 mole = molar mass (g) mole = x 1023 particles* mole = 22.4L
*Particles can be atoms, molecules, ions, or formula units.

3. Understanding Particles
Elements: the smallest particle that represents an element is an atom.
Molecular compounds: the smallest particle that represent a molecular (covalent) compound is a molecule.
Ionic Compounds: the smallest particle that represents an ionic compound is a formula unit.
The 7 diatomic elements H2, N2, O2, F2, Cl2, I2, and Br2 travel as pairs forming a molecule. Even though they are elements, the smallest particle that represents them is a molecule.

4. What type of particle represents the following?
H2O molecule
F2 Molecule

5. Al atom
NiCl3 Formula Unit

6. CCl4 Molecule
Fe2O3 Formula Unit

7. Cl2 Molecule
N2O3 Molecule

8. N3- ion
K atom

9. IF7 molecule
H+ ion

10. Li2SO4 Formula unit
CH4 molecule

11. CO32- ion
CH4 molecule

12. Avogadro constant (the amount in 1 mole)
How large is the amount in 1 mole?
6.02 x 1023 =
Avogadro constant (the amount in 1 mole)

13. How Big Is a Mole?
The volume occupied by one mole of softballs would be about the size of the Earth.
One mole of Olympic shot put balls has about the same mass as the Earth.

14. What is MOLAR MASS?
Molar mass is the weight in grams of one mole of something.
One mole contains x particles.
Therefore, molar mass is the mass in grams of x 1023 things.

15. What is the molar mass of copper?
Take a.m.u and change it to grams… grams Therefore the molar mass of copper is 63.6 g/mol

16. What is the molar mass of molybdenum?
Take and write it in grams … grams.
Thus the molar mass of Mo is g/mol.

17. What is the molar mass of silicon?
If the atomic mass (weight) equals a.m.u.. the molar mass of Si is g/mol.

18. What is the molar mass of water?
1st write the formula: H2O
2nd write how many of each element you have: 2(H) + 1(O)
3rd look up the atomic mass for each element: 2(1.0079) + 1(15.999)
4th write the atomic mass to 1 decimal place: 2(1.0) + 1(16.0)
5th multiply and add: = 18.0
6th write the answer in molar mass units: g/mol
1 mole of H2O is equal to 18.0 grams. Therefore the molar mass of H2O is 18.0 g/mol.

19. What is the molar mass of copper (II) oxide?
1st write the formula: CuO
2nd write how many of each element you have: 1(Cu) + 1(O)
3rd look up the atomic mass for each element: 1(63.55) + 1(15.999)
4th write the atomic mass to 1 decimal place: 1(63.6) + 1(16.0)
5th multiply and add: = 79.6
6th write the answer in molar mass units: g/mol
1 mole of CuO is equal to 79.6 grams. Therefore the molar mass of H2O is 79.6 g/mol.

20. What is the molar mass of sodium sulfate?
Formula is Na+ SO ……. Na2SO4
2(Na) + 1(S) + 4(O) = 2(23.0) + 1(32.0) + 4(16.0)
= g/mol

21. What is the molar mass of dinitrogen pentoxide?
Formula is N2O5
2(N) + 5(O) = 2(14.0) + 5(16.0)
= g/mol

22. What is the molar mass of diatomic fluorine?
38.0 g/mol

23. NOW for the GOOD STUFF Let’s look at how we can convert: Moles Grams
Grams Moles
We will use molar mass as a conversion factor:
𝟏 𝒎𝒐𝒍 𝒎𝒐𝒍𝒂𝒓 𝒎𝒂𝒔𝒔 or 𝒎𝒐𝒍𝒂𝒓 𝒎𝒂𝒔𝒔 𝟏 𝒎𝒐𝒍

24. Example 1: How many grams are in 3.5 moles of Au?
1st identify what is given: 3.5 mol Au
2nd identify what is wanted: grams Au
3rd set-up your work:
𝟑.𝟓 𝒎𝒐𝒍 𝑨𝒖 𝟏 x 𝟏𝟗𝟕.𝟎𝒈𝑨𝒖 𝟏 𝒎𝒐𝒍 𝑨𝒖 =
Given =
Wanted units
689.5 g Au
Your answer should always include correct numerical value, correct units, of what, and should be boxed. This tells that it is your final answer.

25. Example 2: A metal box is made up of 2. 6 moles of lead
Example 2: A metal box is made up of 2.6 moles of lead. How many grams of lead is this equal to?
1st identify what is given: 2.6 mol Pb
2nd identify what is wanted: grams Pb
3rd set-up your work:
𝟐.𝟔 𝒎𝒐𝒍 𝑷𝒃 𝟏 x 𝟐𝟎𝟕.𝟐 𝒈 𝑷𝒃 𝟏 𝒎𝒐𝒍 𝑷𝒃 =
Given =
Wanted units
538.7 g Pb
Your answer should always include correct numerical value, correct units, of what, and should be boxed. This tells that it is your final answer.

26. Example 3: A sample of sand, SiO2, measures 0. 68 moles
Example 3: A sample of sand, SiO2, measures 0.68 moles. How many grams is this?
1st identify what is given: mol SiO2
2nd identify what is wanted: grams SiO2
3rd set-up your work:
𝟎.𝟔𝟖 𝒎𝒐𝒍 𝑺𝒊𝑶𝟐 𝟏 x 𝟔𝟎.𝟏 𝒈 𝑺𝒊𝑶𝟐 𝟏 𝒎𝒐𝒍 𝑺𝒊𝑶𝟐 =
Given =
Wanted units
40.9 g SiO2

27. Example 4: How many grams are in 5.90 moles of KCl?
1st identify what is given: mol KCl
2nd identify what is wanted: grams KCl
3rd set-up your work:
𝟓.𝟗𝟎 𝒎𝒐𝒍 𝑲𝑪𝒍 𝟏 x 𝟕𝟒.𝟔 𝒈 𝑲𝑪𝒍 𝟏 𝒎𝒐𝒍 𝑲𝑪𝒍 =
Given =
Wanted units
440.1 g KCl

28. Example 5: How many moles are in 50.0 grams of tin?
1st identify what is given: g Sn
2nd identify what is wanted: mol Sn
3rd set-up your work:
𝟓𝟎.𝟎𝒈 𝑺𝒏 𝟏 x 𝟏 𝒎𝒐𝒍 𝑺𝒏 𝟏𝟏𝟖.𝟕 𝒈 𝑺𝒏 =
Given =
Wanted units
0.4 mol Sn

29. Example 6: A sample of CaCO3 has a mass of 22. 4 grams
Example 6: A sample of CaCO3 has a mass of 22.4 grams. How many moles is this?
1st identify what is given: g CaCO3
2nd identify what is wanted: mol CaCO3
3rd set-up your work:
𝟐𝟐.𝟒 𝒈 𝑪𝒂𝑪𝑶𝟑 𝟏 x 𝟏 𝒎𝒐𝒍 𝑪𝒂𝑪𝑶𝟑 𝟏𝟎𝟎.𝟏 𝒈 𝑪𝒂𝑪𝑶𝟑 =
Given =
Wanted units
0.2 mol CaCO3

30. Example 7: A sample of NaCl has a mass of 10. 3 grams
Example 7: A sample of NaCl has a mass of 10.3 grams. How many moles is this?
1st identify what is given: g NaCl
2nd identify what is wanted: mol NaCl
3rd set-up your work:
𝟏𝟎.𝟑 𝒈 𝑵𝒂𝑪𝒍 𝟏 x 𝟏 𝒎𝒐𝒍 𝑵𝒂𝑪𝒍 𝟓𝟖.𝟓𝒈 𝑵𝒂𝑪𝒍 =
Given =
Wanted units
0.2 mol NaCl

31. What is the Percent Composition of a Substance?
Percent composition is the percent by mass of each element present in a compound.
NOTE: We cannot take a percentage of an element in a compound by using the counting method because we cannot see atoms – they are extremely small. So we use the mole (Avogadro’ #) and mass to help us do this.

37. Calculating Percent Composition of a Compound?
Formula for water is H2O.
This is 2 moles of H: 2 x 1.0 g = 2.0 grams H
1 mole of O: 1 x 16.0 g = 16.0 g O
The molar mass of water is 18.0 grams.
To calculate percent H, take the mass of H and divide by molar mass, then multiply by 100:
%H = 𝑔 18.0 𝑔 = x 100 = 11.2% H
To calculate percent O, take the mass of O and divide by molar mass, then multiply by 100:
%O = 𝑔 18.0 𝑔 = x 100 = 88.8 % O
Check: the percentage of all elements calculated must = 100%
11.2% % = 100 %

38. Calculating Percent Composition of a Compound?
Formula for hydrogen peroxide is H2O2.
This is 2 moles of H: 2 x 1.0 g = 2.0 grams H
2 mole of O: 2 x 16.0 g = 32.0 g O
The molar mass of water is 34.0 grams.
To calculate percent H, take the mass of H and divide by molar mass, then multiply by 100:
%H = 𝑔 34.0 𝑔 = x 100 = 5.9 % H
To calculate percent O, take the mass of O and divide by molar mass, then multiply by 100:
%O = 𝑔 34.0 𝑔 = x 100 = 94.1 % O
Check: the percentage of all elements calculated must = 100%
5.9 % % = 100 %

39. Which compound has the highest % composition of oxygen by mass, FeO or Fe2O3
FeO: 1 Fe + 1O = 1(55.8) = 1(16.0) = 71.8 g/mol
Take: 𝑔𝑂 71.8 𝑡𝑜𝑡𝑎𝑙 𝑔 x 100 = (0.22)x(100) = 22.0%O
Fe2O3: 2Fe + 3O = 2(55.8) + 3(16.0) = g/mol
Take: 𝑔𝑂 𝑡𝑜𝑡𝑎𝑙 𝑔 x 100 = (0.30)x(100) = 30.0%O
The compound Fe2O3 has the highest percentage of oxygen by mass.

40. Which compound has the highest % composition of iron by mass, FeO or Fe2O3
FeO: 1 Fe + 1O = 1(55.8) = 1(16.0) = 71.8 g/mol
Take: 𝑔𝑂 71.8 𝑡𝑜𝑡𝑎𝑙 𝑔 x 100 = (0.78)x(100) = 78.0%Fe
Fe2O3: 2Fe + 3O = 2(55.8) + 3(16.0) = g/mol
Take: 𝑔𝑂 𝑡𝑜𝑡𝑎𝑙 𝑔 x 100 = (0.70)x(100) = 70.0%O
The compound FeO has the highest percentage of iron by mass.

41. HYDRATE- is an ionic compound that contains water molecules in its structure. A compound in which water molecules are chemically bonded to it.
ANHYDRATE - a hydrate containing no water. The water has been removed by heating, changing pressure, or other means.
ANHYDROUS – containing no water

42. 1MgSO4 ∙ 7H2O Example of Hydrates MgSO4 ∙ 7H2O Na2SO4 ∙ 10H2O
Anatomy of a Hydrate formula
1MgSO4 ∙ 7H2O
Moles of ionic substance
ionic substance
Dot to show water is attached to the salt
Water attached to ionic compound
Moles of water

43. Mole Conversions Mole to Particles/Particles to Moles
REMEMBER
1 mol = Avogadro’s Number = 6.02 × 1023 units
1 mole = molar mass (g) mole = x 1023 particles*
*Particles can be atoms, molecules, ions, or formula units.

44. 1 mol 6.02 × 1023 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠 or 6.02 x 1023 particles 1 mole
Conversions Factors
REMEMBER
1 mol 6.02 × 1023 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠 or x 1023 particles 1 mole
1 mole molar mass (g) or molar mass (g) 1 mole

45. Moles to Particles/Particles to Moles

46. Solving Problems between Moles & Particles
How many atoms are in 5.5 moles of silver?
x x 1023 atoms 1 mole =
want
given
5.5 mol 1
3.3 x 1024 atomsAg

47. Solving Problems between Moles & Particles
How many molecules are in 2.06 moles of CO2?
x x 1023 molecules 1 mole =
want
given
2.06 mol 1
1.24 x 1024moleculesCO2

48. A sample of salt measures 0.738 moles. How many formula units is this?
x x 1023 particles 1 mole =
given
want
4.44 x 1023 formula units
0.738 mol 1

49. A drop of water measures 0. 0120 moles
A drop of water measures moles. How many molecules of water does the drop contain ?
x x 1023 molecules 1 mole =
want
given
7.22 x 1021 molecules
mol 1

50. An iron sample contains 3. 22 x 1024 atoms
An iron sample contains 3.22 x 1024 atoms. How many moles is this equal to?
x 1 mole 6.02 x1023atoms =
want
given
5.35 molFe
3.22 x 1024atoms 1

51. want
How many moles are in a sample of P2O5 containing x 1023 molecules?
x 1 mole 6.02 x =
given
0.221molP2O5
1.33 x 1023molecules 1

52. When converting from particles to grams or grams to particles, always go to moles first: Particles Moles Grams Grams Moles Particles

53. want
How many grams are in a sample of P2O5 containing x 1023 molecules?
x 1 mole 6.02 x =
0.221molP2O5 x g 1𝑚𝑜𝑙 𝑃2𝑂5 = grams
given
0.221molP2O5
1.33 x 1023molecules 1

54. want
How many atoms are in a sample of bismuth weighing grams?
x 1 mole 𝑔 =
0.9594molBi x x mole = x 1023 atomsBi
given
0.9594molBi
200.5 g 1

55. want
How many grams are in a sample of dichlorine heptoxide containing 5.50 x 1024 molecules?
x 1 mole 6.02 x =
9.14 molCl2O7 x g 1𝑚𝑜𝑙 𝐶𝑙2𝑂7 = 1670 grams
given
9.14 molCl2O7
5.50 x 1024 molecules 1

56. want
How many formula units are in a sample of lead (II) chloride having a mass of grams?
x 1 mole 278.1𝑔 =
molPbCl2 x x mole = 4.522x 1023 formula units PbCl2
given
molPbCl2
20.89g 1

57.
You have the opportunity to travel in a time machine into any past era of history. Choose the person who you would like to meet. Write why you would like to meet this person and the importance of his/her influence in your life.
¿Qué persona ha influido más en ti y cómo te ha afectado? Explica la importancia de esta influencia en tu vida.

58. Chemical in the News: