1. 4/5/16 Today I will explain the mole and use it in calculations
Warm Up
What is a dozen?

2. Chapter 10 -The Mole

3. In chemistry, we often use the term “the mole”!

4. The Mole
Mole - The number of atoms of an element equal to the number of atoms in exactly 12.0 g of carbon-12.
How many atoms is that?????

5. There are 602,000,000,000,000,000,000,000 atoms in this sample!
The Mole
There are
602,000,000,000,000,000,000,000
atoms in this sample!

6. 1 mole = 6.02 x 1023 A counting number The Mole 12 2 144 Dozen = ?
Pair = ?
Gross = ? 12 2
144
1 mole =
6.02 x 1023

7. Elements Avogadro’s Number Ionic Compounds Formula units
In chemistry, we use avogadro’s number as the number of atoms, molecules, formula units, ions, etc. in a mole!!! (Particles)
Ionic Compounds
Formula units
Covalent Compounds
Molecules
Elements
Atoms

8. 1 mole of any element = 6.02 x 10 23 particles
The Mole
1 mole of any element = 6.02 x particles
Avogadro’s number!
Examples:
1mol C = 6.02 x atoms C
1mol NaCl = 6.02 x formula units NaCl
1mol SO2 = 6.02 x molecules SO2

9. How big is a mole?

10. THE MOLE
1 mole = 6.02 x 1023 particles We can convert using factor label!!
1. What do you know?
2. Start with what you are given
3. Set up your identity. x
4. Whatever unit is on top goes on the bottom.
5. Plug in conversion factors
6. Cancel Units!
Multiply by top… Divide by bottom.
Answer should have same # of sig figs as given

11. Example How many atoms are in 2.5 moles of tin? 6.02 x 1023 atoms
What do we know about moles and atoms?
1 mole = 6.02 x 1023 atoms!
6.02 x 1023
atoms
2.5 moles x
= 1.5 x 1024atoms 1
mole

12. Example How many moles are equivalent to 550 molecules of SO3?
What do we know about moles and molecules?
1 mole = 6.02 x 1023 molecules!
1 mole
550 molecules x
= 9.1 x mole
6.02 x 1023
molecules

13. Homework
Mole-Particle Conversions

14. 4/6/16 Today I will measure the mass of a mole
Warm Up – What do you know about the mass of an atom?

15. How much is a mole?
The mass of an atom is based on how many protons and neutrons it has.
Since all atoms have different masses, one mole (6.02x1023atoms) would also have different masses!

16. How much is a mole?

17. Mass
Atomic Mass
Based on protons + neutrons
Average of isotopes on the periodic table
Atomic Mass Units
What is the atomic mass of zinc?
65.38 amu
Since the actual mass of an atom is so small, these are relative mass units. Relative to the mass of each atom.

18. Formula Mass
Formula Mass
Sum of the atomic masses for all elements in a compound.
Also in amu

19. Find the atomic mass of each atom rounded to the tenth
Formula Mass
Find the atomic mass of each atom rounded to the tenth
Multiply by the number of each type of atom
Add up the atomic masses (unit amu)

20. Formula Mass Determine the formula mass of acetic acid, HC2H3O2. H –
1.0
x 4 =
4.0
12.0
x 2 =
24.0
16.0
x 2 =
32.0
60.0 amu

21. Molar mass - Mass in grams of 1 mole of any substance.
Equivalent to the formula/atomic mass.
Examples:
Molar mass of Zn = 65.4 g
Molar mass of HC2H3O2 = 60.0 g

22. Mass What’s the difference?
Atomic/Formula mass is the mass on ONE particle (amu)
Molar mass is the mass of 6.02 x particles (g)

23. WHAT DO WE KNOW?
1 mole = 6.02 x 1023 particles 1 mole = molar mass (g)

24. Converting 1 mole = molar mass (g) 1 mole = 18.0g 18.0 g 2.5 moles
What is the mass of 2.5 moles of water (H2O)?
1 mole = molar mass (g)
1 mole = 18.0g
H – x 2 = 2.0
O – 16.0 x 1 = 16.0
18.0g
18.0 g
2.5 moles x
= 45 g
1 mole

25. Converting How many moles in 128 g C6H12O6 (glucose)?
1 mole = molar mass (g)
1 mole = 180.0g
C – 12.0 x 6 =
H – 1.0 x 12 = 12.0
O – 16.0 x 6 = 96.0
180.0g
1 mole
128 g x
= mole
180.0 g

26. Homework Mole-Mass Conversions Remember:
1 mole = 6.02 x 1023 particles
1 mole = molar mass (g)

27. 4/7/16 Today I will measure the number of moles in a gas.
Warm Up – What are our 2 mole conversion factors?

28. MOLAR VOLUME
1 mole of any gas (at STP) will always occupy 22.4 L of space.
STP – Standard Temperature and Pressure
(1 atm and 0°C)

29. THE MOLE
1 mole = 6.02 x 1023 atoms/molecules/F.U.s 1 mole = molar mass (g) 1 mole = 22.4 L (of gas at STP)

30. How many liters are equivalent to 0.25 moles of O2 at STP?
Mole Conversions
How many liters are equivalent to moles of O2 at STP?
1 mole = 22.4 L
22.4 L
0.25 mole x
= 5.6 L
1 mole

31. Homework
1-step mole conversions review

32. 4/8/16 Objective – to perform 2 step molar conversions Warm Up –
What is the molar mass of Mg3(PO4)2?

33. 2 step conversions Molar Conversions
How many grams are in 31.5 L of nitrogen gas (N2) at STP?
We don’t have a conversion that relates grams and liters???

34. Particles (atoms, molecules, fu)
Volume (L)
Mass (g)
Particles (atoms, molecules, fu)
1 mol = 22.4 L
1 mol = molar mass (g)
1 mol = 6.02x1023 p

35. MOLE CONVERSIONS
How many grams are in 31.5 L of nitrogen gas (N2) at STP?
L  mol
1 mole = 22.4 L
mol  g
1 mole = molar mass
1 mole = 28.0g
1 mole
28.0 g
31.5 L x x
= 39.4 g
22.4 L
1 mole

36. Practice Problem #1 How many molecules of hydrogen gas are in 210g H2?
1 mol = molar mass
1 mol = 2.0 g
1 mol = 6.02x1023 molecules
1 mole
6.02x1023 molecules
210 g x x
= 6.3 x molecules
2.0 g
1 mole

37. Practice Problem #2
What is the volume (in L) of x 1024 atoms of Argon?
1 mol = 6.02x1023 atoms
1 mol = 22.4 L
1 mole
22.4 L
2.0x1024 atoms x x
= 74 L
1 mole
6.02x1023 atoms

38. Homework
Two Step Mole Conversions

39. 4/11/16 Objective – to practice mole conversions Warm Up
What is the molar mass of Al2(SO4)3

40. Practice
How many moles are in 5.7 x 1022 molecules of water?

41. Practice
How many molecules are there in 75 grams of MgCl2?

42. Practice
What volume will 3 moles of carbon dioxide occupy?

43. Practice
How many grams are in a 2.3 L balloon full of Xenon?

44. Homework All Mole Conversions Review 42 g 430g (431.36 g)
1 x 1023 molecules (1.34 x 1023)
0.274 mol
100,000 g (125,000)
5 x 1023 molecules (4.816x1023)
240 L (241.86)
3.7 x 1024 atoms
5.27 x 1023 molecules
56.8 L
9440 g (9438.1)
1.34 x 1024 molecules
5.2 mol

45. 4/12/16 Objective – to calculate percent composition Warm Up
How many molecules are in 12.2 L of CO2 gas at STP?

46. Quiz

47. Type 1: Percent Composition
The percent by mass of each element in a compound.

48. Type 1: Percent Composition
Determine the % composition of each element in the following compound:
Na2SO4

49. Type 1: Percent Composition
Determine the % composition of each element in the following compound:
Al2(CO3)3

50. Type 1: Percent Composition
Hydrates – compounds that contain water.
Example : MgSO4  5H2O
Determine the formula mass of this compound. (Here, we want to look at the water separately)

51. Type 2: Percent Composition of Data
Determine the percent composition of a compound that contains 2.20 g sulfur and 3.30g of oxygen.

52. 4/13/16 Today I will continue to solve percent composition problems
Warm Up – What is the percent composition of aluminum chlorate?

53. Type 3: Using Percent composition.
Determine the mass of an element in a given quantity of a compound.
Example: Determine the mass of Ag in 120g of AgCl.
Ag – 107.9x1 = 107.9g
Cl – x1 = 35.5 g
143.4 g
so… % of 120g = mass Ag
0.752 x 120 g = mass Ag
90.2 g = mass Ag
107.9g/143.4g x 100 = 75.2% Ag

54. Type 3: Using Percent Composition
1. Determine the mass of Ca, in 400g of CaCO3.
Answer: 160g.Ca
2. Determine the mass of K, in 50g of KClO34H2O.
Answer: 10.0 g K

55. Homework
Percent Composition & Conversions Review WS

56. 4/14/16 Objective – to determine empirical formulas Warm Up –
What is the percent composition of magnesium nitrate?

57. Determining Chemical formulas
Empirical Formula (Simplest Formula)– Smallest whole number ratio of atoms in a chemical formula.
For ionic compounds, we always have the empirical formula (that’s why we reduce/cancel).
For covalent compounds, the empirical formula can be different from the actual formula!

58. Calculating an Empirical Formula:
1. If given percent: Take the given % and change to grams. (You have assumed 100g) If given grams: Leave them in grams! 2. Convert each value to moles. (using factor label) 3. Divide all answers by the smallest value. (ratio) 4a. If all answers are very close to whole numbers, round to the nearest whole number. b. If not, then multiply each by the same whole number to give a whole number value for all elements. 5. Write the formula with the ratio values as subscripts

59. Answer : Na2SO4 Practice Problem
Find the simplest formula for a compound that contains 32.38% Na, 22.65% S, 44.99% O.
Answer : Na2SO4

60. Answer: K2Cr2O7 Sample Problem
Determine the simplest formula for a compound that contains 26.56% K, 35.41% Cr, 38.08% O.
Answer: K2Cr2O7

61. Review Problem #44.
Find the empirical formula for a compound which contains 6.5g K, 5.9g Cl and 8.0g O.

62. Homework
Empirical Formulas & Mole Review WS

63. 4/15/16
Hydrate Lab

64. 4/18/16 Today I will write molecular formulas
Warm Up - Determine the empirical formula for a compound that is 75% Carbon and 25% Hydrogen.

65. Calculating the Molecular Formulas
Molecular Formula – is a multiple of an empirical formula; tells the actual number of atoms of each element in a molecular compound
For example, if the empirical formula is CO2, possible molecular formulas are C2O4 and C6O12
Molecular Formula = (Empirical Formula)x
“Multiplier”

66. Calculating the Molecular Formulas
Molecular Formula = (Empirical Formula)x Molecular mass – mass of the molecular formula. This must be given in the problem Empirical formula mass – mass of the empirical formula. This is found through calculations

67. Molecular Formula 1st step – determine the empirical formula
2nd step – determine the mass of the empirical formula
3rd step – determine the multiplier (x) *Round to whole #
4th step – multiply empirical formula by x

68. (CH)6 = C6H6 Sample Problem
Determine the molecular formula of a compound having a simplest formula of CH and a formula mass of g
Step 1: Empirical formula is done for you: CH!
Step 2 – Mass of empirical Formula: 13.0g
Step 3
Step 4
(CH)6 = C6H6

69. Sample Problem #2
A compound with a formula mass of 34g is found to consist of .44g H and 6.92g O. What is its molecular formula?

70. Ribose is an important sugar that is found in DNA and RNA
Ribose is an important sugar that is found in DNA and RNA. Ribose has a molar mass of 150 g/mol and a chemical composition of 40.0 % Carbon, 6.67 % hydrogen and 53.3 % oxygen. What is the molecular formula for ribose?

71. Homework
Molecular Formulas WS

72. 4/19/16 Objective – to review problems
Warm Up – How many molecules are in L of CO gas?

73. Types of Problems Mole Conversions Molar Mass One step Two step
% Composition
Type 1 - % comp of formula
Type 2 - % comp of data
Type 3 – Using % comp
Empirical Formulas
Write in grams
Convert to moles
Divide by smallest
Round to whole #
(or multiply)
Make #’s subscripts
Molecular Formulas
Empirical Formula
Mass of Empirical Formula
Multiplier
Multiply

74. 4/20/16 Today I will review chapter 10
The explosive, TNT, is composed of 37.0% C, 2.20% H, 18.5% N and 42.3% O.
a) Determine the empirical formula for TNT.
b) The molar mass for TNT is 227g/mol. What is the molecular formula for TNT?