Moles

1. Stoichiometry - “measuring matter”– Water contamination

– Radon Levels

– Hormone levels in milk

– Impurities in computer chips

Stoichiometry

Moles

H vs HeHe vs CC vs Mg

Atomic Mass

Moles

Mole- Standard Number of atoms or molecules used by chemists

1 mole = 6.022 X 1023 atoms/molecule

Amadeo Avagadro’s Number

Moles

Moles

MolesStoichiometry

Grams Moles Atoms

1 g H 1 mole H 6.02 X 1023 atms

2 g H

12 g C

3 mol C

36.12 X1023 atm He

Grams Moles Atoms

14 g N

42 g N

48 g C

2 mol Na

3 mol Be

36.12 X1023 atm O

30.10 X1023 atm Ca

12.04 X1023 atm Si

MolesStoichiometry

Rounding – 1 decimal place

Iron55.845 g/mole 55.8 g/mol

Sulfur 32.066 g/mole 32.1 g/mol

Oxygen 15.9994 g/mole 16.0 g/mol

Moles

Grams

Moles

Atoms

1. How many Na atoms are present in 11.5 g of Na? (Ans: 3.01 X 1023 atoms)

2. How many C atoms are present in 18.0 g? (Ans: 9.03 X 1023 C)

GMA

Moles

3. What is the mass of 1.20 X 1024 atoms of Na? (Ans: 45.8 grams)

4. What is the mass of 1.51 X 1023 atoms of Be?(Ans: 2.26 g)

5. Start with 0.854 mole V

6. Start with 0.0570 mole Rn

GMA

Moles

How many grams and atoms are in 0.333 moles of Sulfur?

Moles

1. Molar Mass = mass of one mole

2. Units – grams/mole or amu (atomic mass units)

3. What is the molar mass of:1. C

2. O2

3. BaCl2

Molar Mass

MolesMolar Mass

4. What is the molar mass of Cu(NO3)2? (187.5 g/mol)

5. What is the molar mass of Al2(SO4)3? (342.3 g/mol)

Warm-Up

Find everything else if given:

a)0.589 g Ne

b)4.567 X 1024 atoms of K

c)0.00845 mol of Ba

Calculate the molar mass of:

a)KrF4

b)Al(NO3)3

c)Calcium hydroxide

Warm-Up

Find everything else if given:

a)0.589 g Ne (0.0292 mol, 1.76 X1022 atoms)

b)4.567 X 1024 atoms of K (7.58 mol, 297 g)

c)0.00845 mol of Ba (1.16 g, 5.09 X1021 atoms)

Calculate the molar mass of:

a)KrF4 (159.8 g/mol)

b)Al(NO3)3 (213.0 g/mol)

c)Calcium hydroxide (74.1 g/mol)

Moles

1. Monoatomic Elements (C, Fe, Au)GMA

2. Molecules and Ionics (H2O, CaCl2, O2)GMMA

3. You may see “Formula Units” instead of “Molecules” for Ionic compounds

GMMA

Moles

Moles

Grams Moles Molecules Atoms

1 mole of Na

2 mole of Na

1 mole of H2O

1 mole of CH4

3 mole of CH4

GMMA

Moles

1. How many calcium and chlorine atoms are in 200.0 grams of Calcium Chloride?

2. How many hydrogen and oxygen atoms are in 3.60 grams of H2O? (Ans: 2.41 X 1023 atoms H)

GMMA

Moles

3. Given 0.345 mol of Al2(CO3)3, find everything else.

4. Given 3.01X1024 molecules of SO3, find everything else.

5. Given 9.42 X10 22 molecules of C2H4, find everything else.

GMMA

Moles

6. What is the mass of 3.01 X 1022 molecules of Iron(III)Bromide? (Ans: 14.8 g)

GMMA

Moles

1. Given 0.810 g of Mg, find moles and atoms. (0.0333 mol, 2.01X1022 atoms)

2. Given 3.47 X 1022 atoms of fluorine, find grams and moles. (1.10 g. 0.0576 mol)

3. How many carbon atoms are in 36.0 grams of C2H6? (Ans:1.45 X 1024 atoms of C)

4. How many carbon atoms would be needed to weigh the same as one Titanium atom?

Moles

1. How many carbon atoms are in 36.0 grams of carbon? (1.81 X 1024)

2. How many carbon atoms are in 36.0 grams of C2H6? (Ans:1.45 X 1024 atoms of C)

Mixed Examples

Moles

Warm-Up Problems (find everything else)

a) 10.0 g C

b) 10.0 g C2H6

c) 4.00 X 1023 atoms of S

d) 4.00 X 1023 molecules of SO2

e) 0.440 moles of SO2

Mixed Examples

Mixed Examples

Grams Moles Molecules Atoms

10.0 g C 0.833 ======== 5.02 X 1023

10.0 g C2H6 0.333 2.01 X 1023 4.02 X 1023 C

12.1 X 1023 H

21.3 g S 0.664 ======== 4X1023 S

42.6 g SO2 0.664 4X1023 SO24 X 1023 S

8 X 1023 O

28.2 g SO2 0.44 SO2 2.65 X 1023 2.65 X 1023 S

5.30 X 1023 O

164.1 g/mol 197.0 g/mol 234.0 g/mol71.0 g/mol 106.8 g/mol

Moles

1. Definition - % of the elements in a compound by mass

2. Class Example

Girls 12

Boys 13

Percent Composition

Moles

1. What is the % composition of CaCl2? (Ans: 36.1 %, 63.9%)

2. What is the % composition of C2H5OH? (Ans: 52.2 %, 13.0 %, 34.8 %)

3. What is the % composition of Al2(SO4)3? (Ans: 15.8 %, 28.1 %, 56.1 %)

Percent Composition

Moles

1. Definition – The simplest ratio of the elements in a compound

2. Class with6 girls, 9 boys

Empirical Formula

Moles

3. Examples

Formula Empirical Form.

C2H2

Al4S6

C6H12O6

C12H24O12

Empirical Formula

Moles

1. What is the EF of a compound that has 0.900 g Ca and 1.60 g Cl?

Rules

- Go to moles

- Divide by the smaller

Empirical Formula

Moles

2. What is the EF of a compound that is 40.0 % C, 6.67 % H and 53.3 % O?

3. What is the EF of a compound that is 66.0 % Ca and 34.0% P?

4. What is the EF of a compound that is 43.7 % P and 56.3 % O?

Empirical Formula

a. Write the formula of calcium nitrate.b. Calculate the percent composition of

calcium nitrate. (24.4% Ca, 17.1% N, 58.5% O)

c. A compound was analyzed and found to contain 13.5 g Ca, 10.8 g O, and 0.675 g H.  Calculate the empirical formula of the compound? (CaO2H2 or Ca(OH)2)

d. A compound is 69.6% manganese, the rest is oxygen. Calculate the empirical formula.

Moles

1. Empirical – Only tells you the ratios of the elements

2. Molecular – Tells you the true number of each element

Molecular Formula

Moles

EF MF

CH2O CH2O (30 g/mol)

C2H4O2 (60 g/mol)

C3H6O3 (90 g/mol)

C4H8O4 (120 g/mol)

Molecular Formula

Moles

1. What is the MF of benzene if it has an EF of CH and a molar mass of 78.0 g/mol?

2. What is the MF of a compound if it has an EF of AgCO2 and a molar mass of 304.0 g/mol?

Molecular Formula

Moles

3. What is the MF of a compound that is 40.9% C, 4.58 % H and 54.5 % O? It has a molar mass between 350 and 360 g/mol.

4. What is the MF of a compound that contains 4.90 grams of N and 11.2 g of O? The molar mass is about 90 g/mol.

Molecular Formula

Moles1. 33.9% Cu, 14.9% N, 51.2% O

2. 57.5% Na, 40.0% O, 2.5% H

3. 36.1% Ca, 63.9% Cl

4. 70% Fe, 30% O

5. 32% Fe, 27.6% C, 3.5% H, 36.8% O

6. 37.4% Cu, 62.6% Cl

7. 80.2% Ba, 18.7% O, 1.2% H

8. 25.9% N, 74.1% O

9. 60% Ti, 40% O

10.39.8% Cu, 20.1% S, 40.0% O

CaO KMnO4

NH3 N2H4O3

AlI3 H2SO4

KI NaNO3

SO2 H3PO4

K2Cr2O7 C8H8O3

N2H8SO4 As2O3

AgNO3

C2H2O4

C8H16O4

C2H6

C2H4Cl2

C6H4Cl2

N2O4

Moles15 grams mol atoms

a) 0.390 0.017 1 X 1022

b) 1.57 X 106 3.01 X 104 1.81 X 1028

c) 43.2 (Boron) 4.00 2.41 X 1024

d) 4.25 X 10-61.09 X 10-76.55 X 1016

e) 0.123 6.08 X 10-33.66 X 1021

17 a) 41.0 g b) 400. g c) 3.67X106g

19 a) 10.0 mol b) 122 mol c) 3.16X10-

23mol

26. a) 267.6 g/mol b) 119.0 g/mol c) 318.0 g/mol

d) 103.8 g/mol e) 220.0 g/mol

Moles30 Grams Moles Molecules

a) 176 3.67 2.21 X 1024

b) 0.173 3.75 X 10-32.26 X 1021

c) 3.0 X 10-20 2.5 X 10-22 150

d) 49.7 0.141 8.50 X 1022

32.46.7 g/mol

46 a) 3.2%, 19.4%, 77.4%

b) 38.8%, 61.2%

c) 12.7%, 19.7%, 67.6%

d) 12.2%, 5.2%, 27.0%, 56.6%

Moles48 63.6%, 6.0%, 21.2%, 9.3%

57. a) SiO2 b) C2S c) X5Y6 d) Fe2C3O9

59.K2S2O3

61.NH3C3

64.Na2CrO4

67.C3N3O9H5

69. N4S4

72.C6H12O6

88.K2C2O6

Moles Calculate the empirical formula of a compound that contains 55.3 grams of potassium, 14.6 g of phosphorus, and 30.1 g of oxygen.

Moles1. Make up a compound containing 3 elements1. No subscripts >5

2. Use both even and odd numbers

3. Ex: C3O5F2

2. Calculate the percent composition of your imaginary compound. Also calculate the molar mass. Write these numbers down on an index card.

3. Give your card to another group. See if they can determine the formula of your compound.

Moles

Beware the

Mole Man