(WS 1) Dimensional Analysis
Directions: Using Dimensional Analysis, make each of the following conversions. Refer to
the
tables below for necessary conversion factors.
1) 143 miles to meters
Answer:________________
2) 8.8 feet to centimeters
Answer:________________
3) 12.2 cubic feet to liters
Answer:________________
4) 18.000 BTUs to calories
Answer:________________
5) 35.8 gallons to liters
Answer:________________
6) 46 grams per cubic centimeter to pounds per gallon
Answer:________________
7) 26 kilograms per liter to pounds per quart
Answer:________________
8) 8.2 kilograms per cubic meter to pounds per cubic foot
Answer:
9) 0.48 centimeters per day to inches per year
Answer:________________
10) 66.5 kilometers per hour to feet per second
Answer:
2.54 cm = 1in
1 mile = 1609 m
1 meter = 3.28 ft
1 foot = 30.5 cm
1 m3 = 35.3 ft3
1 lb = 454 g
1 ft3 = 28.3 L
1 gal = 3.79 L
1 gal = 3790 cm3
1 L = 1.06 qt
1 kg = 2.205 lb
1 BTU = 252 cal
Moltiple Moles
There are different ways of describing the size of a sample of a substance. We can describe its amount in terms of:
- the mass of the sample
Mass
Mole
# Particles
- the number of particles (atoms or molecules) in the sample
- the volume of the sample at STP, if the sample is a gas
- the number of the moles of particles in the sample
Volume
The first three quantities are all related to one another through the mole. If we know the size of a sample in terms of any
one of the four quantities, we can calculate the amounts of the other three. For example, from a given volume we can
calculate the number of the moles, and from the number of moles we can calculate either the mass or the number of
particles.
Remember:
- One mole of particles (atoms or molecules) has a mass in grams equal to the atomic or molecular mass.
- One mole of particles equals 6.02 x 1023 particles.
- One mole of particles (molecules) has a volume of 22.4 liters at STP, if the sample is a gas.
(WS 2) MOLECULAR WEIGHT AND FORMULA WEIGHT
DIRECTIONS: Find the molecular weight or the formula weight for each of the following compounds.
1. CO
2. NaCl
3. SO2
4. K2S
5. HNO3
6. Cs2SO4
7. Nd2O3
8. Al(OH)3
9. Fe(C2H3O2)2
10.Sb(NO3)3
11. potassium bromide KBr
12. water
13. copper (II) sulfide CuSO4
14. magnesium fluoride MgF2
15. sodium sulfite Na2SO3
16. copper (II) nitrate Cu(NO3)2
17. ammonium bromide NH4Br
18. iron (II) phosphate Fe3(PO4)2
19. magnesium nitride Mg3N2
20. potassium aluminum sulfate * dodecahydrate KAl(SO4)2*12H2O
(WS 3) MOLE CALCULATIONS
DIRECTIONS: Find the number of moles represented by each of the following masses.
1. 17.0 g of NH3
ANSWER:
2. 98.1 g of H2SO4
ANSWER:_
3. 58.5 g of NaCl
ANSWER:
4. 88.0 g of CO2
ANSWER:
5. 0.50 g of hydrogen gas (H2)
ANSWER:
6. 1.582 g of potassium nitrate (KNO3)
ANSWER:
7. 20.0 g of HClO4
ANSWER:
8. 1000. g of aluminum iodide (AlI3)
ANSWER:
9. 0.100 g of copper (II) sulfate (CuSO4)
ANSWER:
10. 50.0 g of phosphoric acid (H3PO4)
ANSWER:
11. 0.2835 g of aluminum sulfite Al2(SO3)3
ANSWER:
12. 30.5 g of Li3PO4
ANSWER:
13. 6.58 g of TmF3
ANSWER:
14. 0.00500 g of gold (III) chloride (AuCl3)
ANSWER:
(WS 4) Moles of Compounds: One Step Problems
EXERCISES
Remember: to help you decide on the correct conversion steps, refer to your “Mole Map”
Convert to Moles.
1) 6.02 x 1023 molecules CO2
2) 1.806 x 1023 molecules C12
3) 1.51 x 1024 molecules H2O
4) 1000. molecules P4O10
5) 4.987 x 1028 molecules HNO3
Mass
Mole
Formula
Mass
# Particles
6.02 x 1023
Convert to mass in grams.
1. 5.0 moles NH3
2. 4.50 moles NaC1
3. 0.30 moles HCl
4. 0.00200 mole Na2SO4
5. 1.50 x 10-4 mole AgC1
Convert to number of molecules.
1. 2.0 moles CO2
2. 1.8 moles PC13
3. 35.0 moles NH3
4. 0.0500 mole SO2
5. 45.8 moles NH4OH
(WS 5) Moles of Compounds: Two-Step Problems
EXERCISES
Remember: to help you decide on the correct conversion steps, refer to your “Mole Map”
Convert to number of molecules.
1) 72 grams HCl
2) 9.0 grams H2O
3) 22 grams CO2
4) 4.500 grams NO
5) 1.00 grams CCl4
Convert to mass in grams.
6) 5.0 x 1023 molecules in C12
7) 3.01 x 1023 molecules SO2
8) 1.81 x 1024 molecules CO2
9) 1000 molecules H2O
10) 6.92 x 1030 molecules CCl4
(WS 6) Moles of Compounds--Mixed Problems
EXERCISES
Remember: to help you decide on the correct conversion steps, refer to your “Mole Map”
Convert to Moles.
1) 4.01 x 1023 molecules CO2
2) 3.02 x 105 grams C12
3) 4.51 x 1026 molecules H2O
4) 1000. grams P2O5
5) 64.56 grams Ca3(PO4)2
6) 1.34 x 1020 molecules NaOH
Convert to mass in grams.
7) 18.0 moles NH3
8) 9.81 x 1025 molecules CO2
9) 3.01 x 1022 molecules SO2
10) 0.0501 moles HCl
11) 1000. molecules H2O
12) 2.50 x 10-4 mole Na2SO4
Convert to number of molecules.
13) 8.46 moles CO2
14) 0.0082 grams CO2
15) 45.0 moles NH3
16) 0.00721 moles HCl
17) 89.4 grams CCl4
18) 8.05 x 10-3 grams H2SO3
(WS 7) The Mole
Mass, Volume and # Particles
In the table below, the size of a sample of the substance is given in one of the four columns. (Columns I, II, III, or IV).
From this given amounts, find the amounts for the other three columns. You will find it helpful to begin the problem by
completing the space in column A. (Give answers to 3 significant figures).
Substance
Column A
Column I
Column II
Column III
Column IV
Molar mass
g/mol
# of moles of
molecules
Mass in
grams
Volume in
liters @ STP
Number of
molecules
210.
1
Cl2(g)
2
NH3(g)
3
F2(g)
4
CO2(g)
5
He(g)
6
C8H18(l)
7
C6H12O6(s)
8
H2S(g)
9
H2O(l)
10
CO(g)
11
CCl4(l)
12
Ar(g)
13
HCl(g)
14
CH3OH(l)
0.500
15
CS2(l)
20.0
5.60
9.03 x 1023
1.00
6.00
6.02 x 1024
360.
11.2
0.0130
9.00 x 1020
30.4
1.80 x 1022
4.48
Mass
Formula
Mass
6.02 x 1023
Mole
22.4 L
Volume
# Particles
(WS 8) PERCENTAGE COMPOSITION
DIRECTIONS: Part A:
Find the percentage composition of the compounds listed below.
A mole of CO2 would weigh 44.0g (you could also consider this as a single molecule in which case it
would be 44.0 amu’s). The weight of the carbon (12.0 g) divided by the total weight (44.0g) x 100
equals the percent composition of carbon. Likewise, oxygen’s percentage is found by dividing its
molar mass (16.0 g) by the total mass.
1. CO
2. KBr
3. H2Te
4. H2SO4
5. Sc(OH)3
6. zinc phosphate Zn3(PO4)2
7. cesium chloride CsCl
8. potassium nitrite KNO3
9. lithium phosphate Li3PO4
10. ammonium carbonate (NH4)2CO3
Part B: Calculate the amount of the element named that is contained in each of the following compounds.
A mole of Fe2O3 would weigh 159.6g. Since there are 2 iron atoms, the iron would weigh 3 x 55.8g
=111.6 g in a mole of the compound. The weight of the iron divided by the total weight equals the
percent composition of iron. Iron’s percent composition multiplied by the mass of the sample (25.0 g)
equals the mass of the iron in your sample.
(1.1)
1. Iron in 25.0 g of Fe2O3
2. Phosphorus in 40.5 g of Ca3(PO4)2
3. Strontium in 5.0 g of SrCl2
4. Carbon in 18.4 g of CaCO3
5. Hydrogen in 100.0 g of calcium acetate Ca(C2H3O2)2
6. Oxygen in 46.45 g of potassium permanganate KMnO4
7. Carbon in 30.8 g of sucrose C12H22O11
8. Bismuth in 4.835 g of sodium bismuthate NaBiO3
(WS 9) SIMPLEST (EMPIRICAL) FORMULA
DIRECTIONS: Part A: Find the empirical formula for each of the compounds whose percentage composition is given
below.
1. 88.8% copper; 11.2% oxygen
2. 40.0% carbon; 6.67% hydrogen; 53.33% oxygen
3. 70.0% iron; 30.0% oxygen
4. 10.1% carbon; 0.9% hydrogen; 89.1% chlorine
5. 12.6% hydrogen; 37.5% carbon; 50.1% oxygen
6. 60.2% terbium; 39.9% chlorine
7. 52.8% aluminum; 47.1% oxygen
8. 81.1% calcium; 18.9 % nitrogen
Part B: Find the empirical formula for each compound listed below. The assay for each is given.
1. 21.52 g potassium; 8.82 g sulfur; 17.62 g oxygen
2. 13.80 g mercury; 1.15 g oxygen
3. 5.91 g magnesium; 17.18 g chlorine
4. 7.28 g barium; 3.74 g chlorine
5. 10.0 g calcium; 4.0 g oxygen
6. 4.78 g potassium; 6.37 g chromium; 6.82 g oxygen
(WS 10) % Composition, Empirical Formula, Molecular Formula
Name_________________
__
Class
Date
Solve each of the following problems showing all work and labels properly.
1)
A compound has an empirical formula of C2OH4 and a molar mass of 88 grams per mole. What is its
molecular formula?
2)
A compound has an empirical formula of C4H4O and a molar mass of 136 grams per mole. What is its
molecular formula?
3)
A compound has an empirical formula of CFBrO and a molar mass of 254.7 grams per mole. What is its
molecular formula?
4)
A compound has an empirical formula of C2H8N and a molar mass of 46 grams per mole. What is its
molecular formula?
5)
What’s the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen?
6)
If the molar mass of the compound in problem 5 is 110 grams/mole, what’s the molecular formula?
7)
What’s the empirical formula of a molecule containing 18.7% lithium, 16.3% carbon, and 65.0% oxygen?
8)
If the molar mass of the compound in problem 7 is 73.8 grams/mole, what’s the molecular formula?