1. 2.C – Conserving Matter

2. When a car’s gas empties, where do the atoms in the gasoline go?

3. Do Now How many and what type of atoms are in the following examples:
A. CH4
B. 4NH3
C. 6Ca(OH)2
D. Al2(NO3)3

4. C.5 The Mole Concept
Definition:
Mole – SI unit for counting
1 Mole of Particles: Contains 6.02 x 1023 particles
Adopted from "Chemistry You Need to Know" by Kelly Deters

5. What is a counting unit?
You’re already familiar with one counting unit…a “dozen”
A dozen = 12
“Dozen” 12
A dozen doughnuts
12 doughnuts
A dozen books
12 books
A dozen cars
12 cars
A dozen people
12 people
Adopted from "Chemistry You Need to Know" by Kelly Deters

6. 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.
Adopted from "Chemistry You Need to Know" by Kelly Deters

7. A Mole of Particles Contains 6.02 x 1023 particles
1 mole C = x 1023 C atoms
1 mole H2O = x 1023 H2O molecules
1 mole NaCl= x 1023 NaCl “molecules”
(technically, ionics are compounds not molecules so they are called formula units)
6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
Adopted from "Chemistry You Need to Know" by Kelly Deters

8. What does a “mole” count in?
A mole = 6.02  1023 (called Avogadro’s number)
6.02  1023 = 602,000,000,000,000,000,000,000
“mole”
6.02  1023
1 mole of doughnuts
6.02  1023 doughnuts
1 mole of atoms
6.02  1023 atoms
1 mole of molecules
6.02  1023 molecules
This means a 12 ounce bottle of water would have
19.7 “moles” of water…a much easier-to-work-with number!
Adopted from "Chemistry You Need to Know" by Kelly Deters

9. Molar Mass What is molar mass?
Adopted from "Chemistry You Need to Know" by Kelly Deters

10. Definition Molar Mass – The mass for one mole of an atom or molecule.
Other terms commonly used for the same meaning:
Molecular Weight
Molecular Mass
Formula Weight
Formula Mass
Adopted from "Chemistry You Need to Know" by Kelly Deters

11. Mass for 1 mole of atoms The average atomic mass = grams for 1 mole
Average atomic mass is found on the periodic table
Element
Mass
1 mole of carbon atoms
12.01 g
1 mole of oxygen atoms
16.00 g
1 mole of hydrogen atoms
1.01 g
Unit for molar mass: g/mole or g/mol
Adopted from "Chemistry You Need to Know" by Kelly Deters

12. Molar mass for molecules
The molar mass for a molecule = the sum of the molar masses of all the atoms
Adopted from "Chemistry You Need to Know" by Kelly Deters

13. Calculating a Molecule’s Mass
To find the molar mass of a molecule: 1
Count the number of each type of atom 2
Find the molar mass of each atom on the periodic table 3
Multiple the # of atoms  molar mass for each atom 4
Find the sum of all the masses
Adopted from "Chemistry You Need to Know" by Kelly Deters

14. Find the molar mass for CaBr2
Example: Molar Mass
Example:
Find the molar mass for CaBr2
Adopted from "Chemistry You Need to Know" by Kelly Deters

15. Find the molar mass for CaBr2
Example: Molar Mass 1
Count the number of each type of atom
Example:
Find the molar mass for CaBr2 Ca 1 Br 2
Adopted from "Chemistry You Need to Know" by Kelly Deters

16. Find the molar mass for CaBr2
Example: Molar Mass 2
Find the molar mass of each atom on the periodic table
Example:
Find the molar mass for CaBr2 Ca 1
40.08 g/mole Br 2
79.91 g/mole
Adopted from "Chemistry You Need to Know" by Kelly Deters

17. Find the molar mass for CaBr2
Example: Molar Mass 3
Multiple the # of atoms  molar mass for each atom
Example:
Find the molar mass for CaBr2 Ca 1 
40.08 g/mole =
40.08 g/mole Br 2 
79.91 g/mole =
g/mole
Adopted from "Chemistry You Need to Know" by Kelly Deters

18. Find the molar mass for CaBr2
Example: Molar Mass 4
Find the sum of all the masses
Example:
Find the molar mass for CaBr2 Ca 1 
40.08 g/mole =
40.08 g/mole Br 2 
79.91 g/mole = +
g/mole
g/mole
1 mole of CaBr2 molecules would have a mass of g
Adopted from "Chemistry You Need to Know" by Kelly Deters

19. Example: Molar Mass & Parenthesis
Be sure to distribute the subscript outside the parenthesis to each element inside the parenthesis.
Example:
Find the molar mass for Sr(NO3)2
Adopted from "Chemistry You Need to Know" by Kelly Deters

20. Example: Molar Mass & Parenthesis
Be sure to distribute the subscript outside the parenthesis to each element inside the parenthesis.
Example:
Find the molar mass for Sr(NO3)2 Sr 1 
87.62 g/mole =
87.62 g/mole N 2 
14.01 g/mole =
28.02 g/mole O 6 
16.00 g/mole = +
96.00 g/mole
g/mole
1 mole of Sr(NO3)2 molecules would have a mass of g
Adopted from "Chemistry You Need to Know" by Kelly Deters

21. Find the molar mass for Al(OH)3
Let’s Practice #2
Example:
Find the molar mass for Al(OH)3
Adopted from "Chemistry You Need to Know" by Kelly Deters

22. Find the molar mass for Al(OH)3
Let’s Practice #2
Be sure to distribute the subscript outside the parenthesis to each element inside the parenthesis.
Example:
Find the molar mass for Al(OH)3 Al 1 
26.98 g/mole =
26.98 g/mole O 2 
16.00 g/mole =
32.00 g/mole H 2 
1.01 g/mole = +
2.02 g/mole
61.00 g/mole
1 mole of Al(OH)3 molecules would have a mass of g
Adopted from "Chemistry You Need to Know" by Kelly Deters

23. Using Molar Mass in Conversions
What is molar mass?
Adopted from "Chemistry You Need to Know" by Kelly Deters

24. Do Now:
Take out your homework.
Find the molar mass of H2O

25. Example: Moles to Grams
How many grams are in 1.25 moles of water?
Adopted from "Chemistry You Need to Know" by Kelly Deters

26. Example: Moles to Grams
When converting between grams and moles, the molar mass is needed
Example:
How many grams are in 1.25 moles of water? H O 2 1
1.01 g/mole
16.00 g/mole  =
2.02 g/mole +
18.02 g/mole
1 mole H2O molecules = g
1.25 mol H2O
18.02
g H2O
= _______ g H2O
22.53 1
mol H2O
Adopted from "Chemistry You Need to Know" by Kelly Deters

27. How many moles are in 25.5 g NaCl?
Let’s Practice #3
Example:
How many moles are in 25.5 g NaCl?
Adopted from "Chemistry You Need to Know" by Kelly Deters

28. How many moles are in 25.5 g NaCl?
Let’s Practice #3
Example:
How many moles are in 25.5 g NaCl? Na Cl 1
22.99 g/mole
35.45 g/mole  = +
58.44 g/mole
1 mole NaCl molecules = g
25.5 g NaCl 1
mole NaCl
= _______ mole NaCl
0.44
58.44
g NaCl
Adopted from "Chemistry You Need to Know" by Kelly Deters

29. Example: Grams to Molecules
How many molecules are in
25.5 g NaCl?
Adopted from "Chemistry You Need to Know" by Kelly Deters

30. Example: Grams to Molecules
How many molecules are in
25.5 g NaCl? Na Cl 1
22.99 g/mole
35.45 g/mole  = +
58.44 g/mole
1 moles NaCl molecules = g
1 mol = 6.021023 molecules
25.5 g NaCl 1
mol NaCl
6.021023
molecules NaCl
58.44
g NaCl 1
mol NaCl
= _________ molecules NaCl
2.63  1023
Adopted from "Chemistry You Need to Know" by Kelly Deters

31. Practice: Solve the following problem:
How many moles are in 6.7 g of NaCl?
Given: Attain:

32. Objectives SWBAT practice conversions between moles and grams
SWBAT practice conversions between moles and molecules

33. How many moles are in a sample of 2.75 × 1024 molecules of SrCl2?
Let’s Practice #4
Example:
How many moles are in a sample of 2.75 × 1024 molecules of SrCl2?
Adopted from "Chemistry You Need to Know" by Kelly Deters

34. How many moles are in a sample of 2.75 × 1024 molecules of SrCl2?
Let’s Practice #4
Example:
How many moles are in a sample of 2.75 × 1024 molecules of SrCl2?
1 mol = 6.021023 molecules
2.75 × 1024 molecules
SrCl2 1
mol SrCl2
6.02 × 1023
molecules
SrCl2
= __4.56__ mol SrCl2
Adopted from "Chemistry You Need to Know" by Kelly Deters

35. REMEMBER: If you are going between moles and mass use MOLAR MASS.
1 mole molar mass (g)
molar mass (g) mole
If you are going between moles and molecules (atoms) use AVOGADROS NUMBER.
6.02 X 1023 molecules 1 mole
1 mole X 1023 molecules

36. Practice: Solve the following problem:
How many molecules are in 0.8 moles of NaCl?
A. Given: Unknown (attain):
B. What is your conversion factor?
C. Solve:

37. GRAMS to MOLECULES
How many molecules are in 4.6 grams of HCl?

38. Objective
1. SWBAT review problems where molar mass converts between moles and grams.
2. SWBAT determine molar relationships amount reactants and products in a chemical equation.

39. Practice: Solve the following problem:
How many moles are in 2.8 g of HCl?
A. Given: Unknown (attain):
B. What is your conversion factor?
C. Solve:

40. DO NOW 1. How many moles are in 2.3 X 1024 molecules of NaCl?
2. How many moles are in 6.8 X 1026 molecules of CO2?
3. How many molecules are in 2.3 moles of HCl?
Adopted from "Chemistry You Need to Know" by Kelly Deters

41. Objectives
1. SWBAT define the law of
2. SWBAT review
3. SWBAT balance

42. Keeping Track of Atoms
Law of Conservation of Matter: Matter is neither
Since chemical reactions cannot create or destroy atoms, chemical equations representing the reactions must always be __________

43. Atomic Perspective: C O2  CO2
1 Carbon atom oxygen molecule  carbon dioxide molecule
What are the reactants in this chemical equation?
What are the products in this chemical equation?
Are there the same number of atoms on both sides of the equation?
Where any atoms destroyed or created?
Was the Law of Conservation of Matter maintained?

44. 2 Cu (s) + O2 (g)  2 CuO (s)
COEFFICIENTS - indicates the number of units of each substance involved.
Does the oxygen molecule have a coefficient?
What do the subscripts represent?
Can subscripts be removed from chemical equations?

45. DO NOW 2 Cu (s) + O2 (g)  2 CuO (s)
What are the reactant(s) in this chemical equation?
What are the product(s) in this chemical equation?
Are there the same number of atoms on both sides of the equation?
Where any atoms destroyed or created?
Was the Law of Conservation of Matter maintained?

46. How do we Balance Equations?
Number of compounds in the reaction
Coefficients
2 H2 + O2  2 H2O
Subscripts
# of atoms in a compound
________ balance charges within a _______.
_________ balance atoms in an _______

47. What do Coefficients Really Mean?
CH4 + 2 O2  CO2 + 2 H2O
Total:
1 C
4 H
4 O
Total:
1 C
4 H
4 O
The equation is ________.

50. Make an atom inventory for the following equation
Al2O3 + HCl -> AlCl3 + H2O
Is it Balanced?

51. SWBAT
Practice _________ equations in groups.

52. How to Balance By Inspection:1
Make a ________ of elements
_____ C H4 +
_____ O2 
_____ H2 O +
_____ C O2
Reactants
Products C H O
Taken from Kelly Deters

53. How to Balance By Inspection:2
...
Don’t forget to add all the atoms of the same element together—even if it appears in more than one compound!
_____ C H4 +
_____ O2 
_____ H2 O +
_____ C O2
Reactants
Products C 1 1 H 4 2 O 2 3
Taken from Kelly Deters

54. How to Balance By Inspection:3 .
Each time you add a coefficient, update your table with the new quantities of each atom.
_____ C H4 +
_____ 2 O2 
_____ 2 H2 O +
_____ C O2
Reactants
Products C 1 1 H 4 2 4 O 2 4 3 4
Taken from Kelly Deters

55. How to Balance By Inspection:4 .
Filling each coefficient location lets you and the grader know that you finished the problem rather than you left some blank because you weren’t done!
_____ 1 C H4 +
_____ 2 O2 
_____ 2 H2 O +
_____ 1 C O2
Reactants
Products C 1 1 H 4 2 4 O 2 4 3 4
Taken from Kelly Deters

56. Choosing the Order of Balancing
How do you know what order to balance in?
Start Elements that appear only 1 time per side
Save for later
Elements that are uncombined
Pb + PbO2 + H+  Pb2+ + H2O
Start Elements in most complicated molecules
Save for later
Elements that appear more than 1 time per side
To balance this equation, use the order:
Taken from Kelly Deters

57. How is Balancing Affected by Order?
What happens if we balance in the order determined in the last slide?
_____ 1 Pb +
_____ 1 Pb O2 +
_____ 4 H+ 
_____ 2 H2 O +
_____ 2
Pb2+
Reactants
Products O 2 1 2 H 1 4 2 4 Pb 2 1 2
Taken from Kelly Deters

58. What about a different order?
How is it different if we balance in a different order? 4
_____ 1 Pb +
_____ 1 Pb O2 +
_____ 2 H+ 
_____ 2 H2 O +
_____ 2
Pb2+
Reactants
Products  H 1 2 4 2 4 O 2 1 2 Pb 2 1 2
You’ll still get to the correct answer, but it will take longer and be more complicated!
Taken from Kelly Deters

59. Balance the following equation
Let’s Practice #1
Example:
Balance the following equation
__ HCl + __ Ca(OH)2  __ CaCl2 + __ H2O
Taken from Kelly Deters

60. Balance the following equation
Let’s Practice #2
Example:
Balance the following equation
__ H2 + __ O2  __ H2O
Taken from Kelly Deters

61. Balance the following equation
Let’s Practice #3
Example:
Balance the following equation
__ Fe + __ O2  ___ Fe2O3
Taken from Kelly Deters

62. Do Now Balance the following equations:
__Cu +__AgNO3 -> __Cu(NO3)2 + __Ag
___NaClO3 --> ___NaCl + ___O2

63. Objectives
1. SWBAT define ...
2. SWBAT calculate the ..

64. Do Now Take out your homework. Take out a calculator.
___H2O _____H2O + _____O2

65. Objectives
SWBAT determine the
SWBAT convert

66. Objectives SWBAT practice conversions between moles and grams
SWBAT practice conversions between moles and molecules

67. Steps to Solving Equations and Molar Relationships
1. Balance the equation.
2. State the GIVEN and what you want to ATTAIN (UNKOWN)
3. Figure out conversions.
4. SOLVE!

68. WORKSHEET PROBLEM #1 MOLES TO MOLES
___Mg + ____O2 -> ____MgO
How many moles of Mg are needed to produce 6 moles of MgO?
How many moles of O2 are needed to produce 4 moles of MgO?
How many moles of MgO will be produced when 7 moles O2 enter the reaction?

69. PROBLEM #1 MOLES TO MOLES to Grams
2H2O2 -> 2H2O + O2
How many grams of H2O2 are needed to produce 6 moles of O2?

70. DO NOw For the following equation: ____Cu + ____O2 -> ____CuO
1. How many moles of Cu are needed to react with 15 moles O2?
2. How many moles of CuO produced when 11 moles Cu react with sufficient O2?

71. Objectives SWBAT calculate moles of product and moles of reactants.
SWAT answer questions on molar mass, g to molecules, and stoichometry.

72. DO NOW: ___C5H12 + ___O2 --> ___CO2 + ___H2O
If 10 moles of C5H12 enter the reaction, how many moles of H2O are produced?
If 13 moles CO2 are produced, how many moles O2 went in?
If 10 moles of C5H12 enter the reaction, how many grams of H2O are produced?

73. Do Now
2Cu + O2 -> 2CuO
How many moles of Cu are needed to react with 5.6 moles O2 ?
How many grams of Cu will be needed to react with 5.6 moles O2 ?

74. Objectives 1. SWBAT calculate percent compositions.
2. SWBAT explain why knowledge of percent compositions is important to the mining process.

75. Percent Composition
Percent by mass of each material found in a formula unit.
Ex. In Cu2S, it is 80% copper.

76. Determining Percent Composition
1. Find the molar mass of the formula unit.
2. Find the percentage by dividing the part by the whole and multiplying by 100.

77. Example

78. Let’s Try this one Find the percent oxygen in the following formulas:
CO2
C6H12O6

79. Think-Pair-Share

80. How is percent composition important when mining metals?
How is it important when selecting your metal for your coin?

81. Do Now
What percent of oxygen is found in Calcium Nitrate? Ca(NO3)2