Complete the following reactions:
Lithium Sulfate dissolves in water
Moles
Potassium metal combines with bromine
Benzene (C6H6) combusts in oxygen
Copper(II)sulfate reacts with sodium hydroxide
Stoichiometry
1. Stoichiometry - “measuring matter”
–
–
–
–
Water contamination
Radon Levels
Hormone levels in milk
Impurities in computer chips
Sodium metal reacts with silver(I) nitrate
Moles
H vs He
He vs C
C vs Mg
Atomic Mass
Moles
Amadeo Avagadro’s Number
1776–1856
Mole- Standard Number of atoms
or molecules used by chemists
1 mole = 6.022 X 1023
atoms/molecule
(measured by Jules Perrin, 1908
Nobel Prize 1926)
Moles
Moles
1
Moles
Stoichiometry
Grams
Moles
1gH
1 mole H
Grams
Atoms
14 g N
42 g N
Atoms
6.02 X 1023 atms
48 g C
2 mol Na
2gH
3 mol Be
12 g C
36.12 X1023 atm O
3 mol C
30.10 X1023 atm Ca
36.12 X1023 atm He
Moles
Stoichiometry
Rounding – 1 decimal place
12.04 X1023 atm Si
Moles
GMA
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)
Iron
55.845 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
Moles
GMA
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
How many grams and atoms are in 0.333 moles of
Sulfur?
How many grams and moles are in 3.01 X 1024
atoms of oxygen?
2
Moles
Molar Mass
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
Moles
Molar 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
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
b) Al(NO3)3
c) Calcium hydroxide
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)
Warm-Up
Find everything else if given:
a) 4.567 X 1024 atoms of K
b) 0.00845 mol of Ba
Warm-Up
Find everything else if given:
a) 4.567 X 1024 atoms of K (7.58 mol, 297 g)
b) 0.00845 mol of Ba (1.16 g, 5.09 X1021 atoms)
Calculate the molar mass of:
a) Al(NO3)3
b) Calcium hydroxide
Calculate the molar mass of:
a) Al(NO3)3 (213.0 g/mol)
b) Calcium hydroxide (74.1 g/mol)
3
Moles
GMMA
Moles
1. Monoatomic Elements (C, Fe, Au)
GMA
2. Molecules and Ionics (H2O, CaCl2,
O 2)
GMMA
3. You may see “Formula Units” instead
of “Molecules” for Ionic compounds
Moles
Grams
GMMA
Moles
Molecules Atoms
1 mole of Na
2 mole of Na
1 mole of H2O
1 mole of CH4
3 mole of CH4
3. Given 0.345 mol of Al2(CO3)3, find
everything else.
4. Given 3.01X1024 molecules of SO3,
find everything else.
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: 1.20 X 1023 atoms O, 2.40 X
1023 atoms H)
6. What is the mass of 3.01 X 1022
molecules of Iron(III)Bromide? (Ans:
14.8 g)
5. Given 9.42 X10 22 molecules of
C2H4, find everything else.
4
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
Mixed Examples
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
Moles
Empirical Formula
1. Definition – The simplest ratio of the
elements in a compound
2. Class with
6 girls, 9 boys
Moles
Mixed Examples
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)
Grams
Moles
10.0 g C
0.833
Mixed Examples
========
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 SO2
28.2 g SO2
0.44 SO2
2.65 X 1023
4 X 1023 S
8 X 1023 O
2.65 X 1023 S
5.30 X 1023 O
164.1 g/mol
71.0 g/mol
Moles
Molecules
197.0 g/mol
106.8 g/mol
Atoms
234.0 g/mol
Empirical Formula
3. Examples
Formula
Empirical Form.
C2H2
Al4S6
C6H12O6
C12H24O12
5
Moles
Empirical Formula
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
5. Calculate the empirical formula of a
compound that is 13.05 % boron. The rest
is oxygen. (B2O9)
6. A borane is a compound containing only
boron and hydrogen. A 35.00 gram sample
is analyzed and contains 30.96 grams of
boron. Calculate the empirical formula.
(B5H7)
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?
A1B1.25
A1B1.33
A1.2B1
A1B2.67
A1B1.75
Moles
Molecular Formula
1. Empirical – Only tells you the
ratios of the elements
2. Molecular – Tells you the true
number of each element
EF
CH2O
MF
CH2O
C2H4O2
C3H6O3
C4H8O4
(30 g/mol)
(60 g/mol)
(90 g/mol)
(120 g/mol)
6
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?
Moles
Percent Composition
1. Definition - % of the elements in a
compound by mass
2. Class Example
Girls
8
Boys
6
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.
Moles
Percent Composition
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 %)
Calculate the empirical formula of a compound
Moles
(24.4% Ca, 17.1% N, 58.5% O)
that contains 55.3 grams of potassium, 14.6 g of
phosphorus, and 30.1 g of oxygen.
How many oxygen atoms would be in 50.0 grams
of this compound?
7
1. Make up a compound containing 3 elements
Moles
1. 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.
14. grams
Moles
a) 14.5
b) 150.
c) 27.0
d) 363(Ge)
e) 7.95X10-23
15 grams
Moles
a) 0.390
b) 1.57 X 106
c) 43.2 (Boron)
d) 4.25 X 10-6
e) 0.123
17 a) 41.0 g
19 a) 10.0 mol
mol
0.468
1.75
1.00
5.00
1.66X10-24
mol
0.017
3.01 X 104
4.00
1.09 X 10-7
6.08 X 10-3
b) 400. g
b) 122 mol
atoms
2.82 X 1023
1.05 X 1024
6.02 X 1023
3.01 X 1024
1.00
atoms
1 X 1022
1.81 X 1028
2.41 X 1024
6.55 X 1016
3.66 X 1021
c) 3.67X106g
c) 3.16X10-23mol
Moles
Ba = 68.7%
Co = 19.6%
N = 11.7%
MM ~ 600 amu
15 grams
Moles
a) 0.390
b) 1.57 X 106
c) 43.2 (Boron)
d) 4.25 X 10-6
e) 0.123
mol
0.017
3.01 X 104
4.00
1.09 X 10-7
6.08 X 10-3
atoms
1 X 1022
1.81 X 1028
2.41 X 1024
6.55 X 1016
3.66 X 1021
16.a) 63.5 g
17.a) 41.0 g
b) 16.1 g
b) 400. g
c) 40.1 g
c) 3.67X106g
25. a) 106.6 g/mol b) 80.1 g/mol c) 108.0 g/mol
Moles
d) 98.1 g/mol e) 106.0 g/mol f) 60.0 g/mol
g) 459.7 g/mol
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
27. Cr2(SO4)3 392.3 g/mol
28. Sr(ClO4)2 286.6 g/mole
8
30 Grams
Moles
Moles
3.67
3.75 X 10-3
2.5 X 10-22
0.141
Molecules
2.21 X 1024
2.26 X 1021
150
8.50 X 1022
a) 176
b) 0.173
c) 3.0 X 10-20
d) 49.7
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%
Converting between Grams and Moles
a) 0.118 mol
l) 0.167 mol
b) 98.25 g
m) 55.6 g
c) 2.55 mol
n) 0.595 mol
d) 54.0 g
o) 81.0 g
e) 0.250 mol
p) 0.292 mol
f) 2.24 mol
q) 0.445 mol
g) 104 g
r) 426 g
h) 2.00 mol
i) 189 g
j) 0.547 mol
k) 20.5 g
More Converting using grams and molecules
1. 2.51 X 1023 atoms
2. 9.26 X 1021 molecules
3. 1.01 X 1024 atoms H
4. 1.05 X 1024 formula units
5. 2.26 X 1024 atoms O
6. 2.07 X 1024 atoms O
7. 5.03 X 1023 atoms O
8. 1.41 X 1024 atoms Cl
9. 1.64 X 1023 atoms N
10.2.28 X 1021 atoms C
46 a) 3.2%, 19.4%, 77.4%
Moles
b) 38.8%, 61.2%
c) 12.7%, 19.7%, 67.6%
d) 12.2%, 5.2%, 27.0%, 56.6%
48. 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
Converting using molecules and atoms
a. 1.02 X 1022
k. 3.19 X 1023 atoms H
21
b. 2.18 X 10
l. 2.50 X 1023 atoms Cl
c. 4.74 X 1020
m. 19.4 g
d. 0.123 g
n. 2.95 g
e. 27.6 g
f. 1.33 X 10-22 g
g. 5.90 X 10-23 g
h. 401 g
i. 3.38 X 1023 atoms
j. 1.81 X10 22 atoms
1. 33.9% Cu, 14.9% N, 51.2% O
Moles
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
9
1. CaO
2. NH3
3. AlI3
4. SO2
5. K2Cr2O7
6. N2H8S
7. AgNO3
8. KMnO4
9. H3PO4
10. H2SO4
11. C8H8O3
12. As2O3
Answers to Review Sheet:
1.
A
11. A
2.
D
12. D
3.
E
13. D
4.
D
14. A
5.
A
15. E
6.
C
7.
A
8.
A
9.
C
10. E
Molecular (True) Formula
1. C2H2O4
2. C8H16O4
3. C2H6
4. C2H4Cl2
5. C6H4Cl2
6. N2O4
Moles
Beware the
Mole
Man
10