Chapter 10 - Chemical Quantities
Chemistry
Mr. Hines
PART A – CHEMICAL QUANTITIES, THE BASICS
Learning Targets and “I can” statements
1. Recall basic facts from the periodic table.
2. Recall basic concepts of mass.
3. Measure mass in atomic mass units (amu)
4. Recall facts about isotopes
5. Define conversion, conversion factor, and dimensional analysis.
6. Use dimensional analysis to perform basic conversions (chapter 3)
7. Convert “counting numbers” to “dozens” (forwards and backwards)
8. Define the mole and Avogadro’s number
9. Explain how the mole is useful.
10. Define Representative Particles and list examples.
I CAN
PART B – CHEMICAL CALCULATIONS
11. Convert Number of Representative particles to Moles (page 291)
12. Convert moles to number of representative particles.
13. Determine the molar mass of a substance
14. Convert moles to mass in grams
15. Convert mass in grams to moles. (Page 299)
16. Convert grams of a substance to the number of representative particles.
17. Convert the number of Representative particles to grams.
PART C - PERCENT COMPOSITION AND CHEMICAL FORMULAS
18. Calculate the percent composition of a compound when given the formula
19. Calculate percent composition from mass data (page 306)
20. Determine the empirical formula when given the molecular formula
Vocabulary
Mole
Neutron
Amu
Unit
Directly
proportional
Convert
Celsius
Gram
Mass
Electron
Volume
Whole number
Avogadro’s
number
Molar mass
Liter
Pound
Atomic mass
Atom
Matter
Isotopes
Representative
particle
compound
Molecular formula
Empirical formula
Atomic number
Element
Weight
Carrot
Significant figure
gas
Ratio
Counting number
Proton
Percent
Formula
particle
Percent
composition
temperature
GCF
Dozen
PART A – CHEMICAL QUANTITIES, THE BASICS
Target 1 – Recall basic facts from the periodic table.
A.
B.
C.
D.
Notes box
Remember that the atomic _________________equals the number of protons in an atom.
Also, the atomic MASS equals the total number of protons and neutrons in an atom.
Protons and neutrons are also known as _________________(atomic mass units)
The atomic number is listed above a symbol and the atomic mass is listed below.
Target 2 – Recall basic concepts of mass.
A. The mass of most matter in our daily lives can be measured in ______________________.
B. The mass of an object can be determined by measuring its weight using a scale or balance.
C. On the planet Earth, mass and weight are the _________________ thing.
D. The mass of an object is directly proportional to the amount of atoms it is made of.
E. More specifically, the mass of an __________ is directly proportional to the number of amu it contains.
F. For example, the atomic mass of Carbon is 12 amu and the atomic mass of Helium is 4 amu.
G. Therefore, Carbon has a greater mass than Helium and Carbon will ______________more than Helium.
H. Electrons do not account for mass since they are so small (almost nothing)
Notes box – Be
C
O
Ne
Questions 
1. If you want to know how many protons an element has, you look at the _______________________
2. If you want to know how many amu an element has, you look at the __________________________
3. If you want to know how many neutrons an element has, you …..
__________________________________________________________________________________
4. How do you determine the mass of an object? ___________________________________________
5. Circle the answer that has the greatest mass.
Ten Hydrogen atoms
Five Lithium atoms
Three Helium atoms
Target 3 - Measure mass in atomic mass units (amu)
A. Since atoms have such small masses, using the units of grams is hardly useful when talking about
individual _________________________.
B. For example, a carbon atom has a mass of 1.99 x 10-23 grams
Write it –
C. Instead of using grams to express the mass of atoms, we will us atomic mass units (amu)
D. For now, we will give all individual particles found in the nucleus an atomic ____________ of 1 amu.
E. In other words, the atomic mass equals the number of atomic mass units (amu) of an atom.
F. To determine the atomic mass of an atom, you count the particles in the _______________________.
Complete the chart
Element
Protons
He
N
S
Ga
K
Neutrons
Total
neutrons and
protons
Atomic mass
units (amu)
Atomic mass
H2 O
CO2
Calcium
Oxide
 Questions
1. What does “amu” stand for? ____________________________________________
2. How many amu are in 1 atom of Helium? __________
3. How many amu are in 2 atoms of Helium? __________
4. How many amu are in 1 atom of Iron? __________
5. How many amu are in 9 atoms of Iron? ___________
6. How many amu are in 1 atom of Potassium? __________
7. How many amu are in 4 atoms of Potassium? _________
8. If Amelium has 345 protons and 400 neutrons, what is the atomic mass of Amelium? _______
9. How many amu are in 1 atom of Amelium? ________
Target 4 – Recall facts about isotopes
A. The atomic mass of each element is not a __________________ number. (Cl = 34.45)
B. This is because there are different isotopes of most elements. (You can look this up in chapter 4)
C. Isotope - element that has a different number of __________________.
D. The atomic mass is calculated by the AVERAGE of its abundance in nature.
Target 5 – Define conversion, conversion factor, and dimensional analysis.
A. Conversion - method where a measurement is rewritten using different ______________.
B. Conversion factor – written expression of 2 different units representing equivalence.
Example: 1 pound = 454 grams
Dimensional analysis - most common method for ____________________ various units of measurement
Target 6 – Use dimensional analysis to perform basic conversions (chapter 3)
You must show your work to receive full credit
1) 45.200 pounds to grams
2) 356 grams to pounds
3) 6.290 pounds to grams
4) 7.266 ounces to grams
5) 225 ounces to pounds
6) 634 grams to pounds
6) .607 kilograms to pounds
7) 24.5 pounds to tons
8) 3.23 x 109 grams to pounds
9) 9.71 x 10-2 pounds to grams
Target 7 – Convert “counting numbers” to “dozens” (forwards and backwards)
1. In order to make numbers more manageable, we have various units which measure the same thing.
2. For example – You might say “I have 24 bananas.”
3. You could also say “I have 2 dozen bananas.”
4. If you understand what a dozen means, then you know that 24 bananas and 2 dozen bananas is the same
amount.
1 dozen = 12
Perform these conversions using dimensional analysis. (don’t forget sig figs)
You must show your work to receive full credit.
1) 35 bananas = ______________ dozen bananas
3)11.0 dozen jellybeans = __________ jellybeans
2) 72 apples = _______________dozen apples
4) 31.4 dozen chickens = ___________ chickens
Target 8 – Define the mole and Avogadro’s number
A. What is a mole? A ______________ is a conversion factor that is helpful to make very large numbers
more understandable.
B. 1 mole = 602,000,000,000,000,000,000,000. (1 mole = six with 23 zeros!)
C. 1 dozen = 12
D. 1 Mole = the amount of a substance that contains 6.02 x 1023 representative particles of that substance.
E. 1 mole of strawberries = 602,000,000,000,000,000,000,000 strawberries.
F. 1 mole of strawberries = 6.02 x 1023 strawberries
G. 1 dozen strawberries = 12 strawberries
H. In chemistry, we deal with so many particles that we need to make the numbers more manageable.
I. So instead of saying we have 6.02 x 1023 particles, we say we this is “1 mole.”
J. Avogadro’s number = the number of particles in 1 mole.
K. Avogadro’s number = 602,000,000,000,000,000,000,000.
L. In other words, if you have 1 mole of anything - you have 602,000,000,000,000,000,000,000.
M. ONE MOLE = 602,000,000,000,000,000,000,000
N. ONE DOZEN = 12
O. Where did Avogadro get this number? He figured out that 1 gram of anything has 6.02 x 1023 amu.
Target 9 –Explain how the mole is useful.
A. If one gram of anything has 6.02 x 1023 amu, then we can __________________any object and
determine how many amu it contains.
B. From this information, we can calculate how many atoms it is made of.
C. So what is a particle? A ________________________in chemistry can be protons, neutrons, electrons,
amu, atoms, or molecules…others.
D. The mole is useful because it help chemists (you) predict the amount of atoms in an object.
 Questions
1. What is a mole in chemistry? ____________________________________________________
2. If you had 1 dozen of dogs, how many dogs would you have? ____________
3. If you had 1 mole of dogs, how many dogs would you have? _______________________________
4. 1 dozen equals ______________________
5. 1 mole equals __________________________________________________ (standard form)
6. 1 mole equals __________________________________________________ (scientific notation)
7. Write Avogadro’s number in standard form. ___________________________________________
8. Write Avogadro’s number in scientific notation. ________________________________________
9. Where did Avogadro get this number? ________________________________________________
 Fun facts about the mole 
1. While a dozen eggs will make a nice omelet, a mole of eggs will fill all of the oceans on earth more
than 30 million times over.
2. 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
Target 10 – Define Representative Particles and list examples.
A. Representative particles – The building blocks of a substance.
B. For example, water is made of 2 Hydrogen atoms and 1 oxygen atom. A representative particle of water
is a molecule with the formula H2O. See chart below.
Representative particles
Name
Formula
Water
H2 O
Representative
particle
Molecule
diagram
Glucose
C6H12O6
Molecule
Iron
Fe
Atom
Helium
He
?
?
Carbon dioxide
CO2
?
?
PART B – USING AVOGADRO’S NUMBER IN CALCULATIONS
Target 11 - Convert Number of Representative particles to Moles (page 291)
Step 1 – Read the question and determine what it is asking.
Step 2 - Write down what information is given (identify the representative particle).
Step 3 – Write down the proper conversion.
Step 4 – Set up the problem using dimensional analysis.
Step 5 – Enter numbers into calculator and write down the answer.
****Remember – Representative particles can be atomic mass units (amu), atoms, or molecules.
1 mole = 6.02 x 1023 representative particles
Magnesium is a light metal used in the manufacture of aircraft, automobile wheels, tools, and garden
furniture. How many moles of magnesium is equal to 1.25 x 1023 atoms of magnesium?
Step 1
Step 4
Step 2
Step 5
Step 3
Practice – Show your work for full credit.
1. How many moles of Helium is equal to 3.55 x 1024 atoms of Helium?
2. How many moles of Carbon dioxide is equal to 4.22 x 1022 molecules of Carbon dioxide?
3. How many moles of Calcium is equal to 3.66 x 1022 atoms of Calcium?
4. How many moles of water is equal to 8.33 x 1017 molecules of Water (dihydrogen monoxide)?
Target 12 - Convert moles to number of representative particles.
Oxygen is a gas found in Earth’s atmosphere and is necessary to keep you alive. How many atoms are
in 2.12 moles of Oxygen?
Step 1
Step 4
Step 2
Step 5
Step 3
Practice – Show your work for full credit.
1. How many atoms of silicon are equal to 7.99 moles of silicon?
2. How many molecules of glucose are equal to 4.66 moles of glucose?
3. How many atoms of Iron are equal to 9.22 moles of Iron?
4. How many molecules of Potassium chloride are equal to 1.445 moles of Potassium chloride?
Target 13: Determine the molar mass of a substance.
1. In chemistry it is important to be able to convert from moles of a substance to the mass in grams.
2. Molar mass – the mass in grams of one _____________ of a given substance.
3. In other words, molar mass tells how much 1 mole of a substance weighs.
4. The atomic _______________ will give you this value for each element (number below the symbol)
5. For example, the atomic mass of Copper is 63.55 amu. This means that 1 mole of Copper will weigh
63.55 grams.
6. Don’t forget that mass is related to the number of amu. More amu will cause ______________ mass.
7. Molar mass of an element can be used as a conversion from moles to mass and vice versa.
8. For these calculations, we always use atomic mass to the hundredth decimal place. (Boron = 10.81 amu)
Molar mass of Elements
Element
Moles
Hydrogen
1
grams
Element
Hydrogen
Moles
2
Lithium
1
Lithium
2
Oxygen
1
Oxygen
3
Argon
1
Argon
2.4
grams
Molar mass of compounds
Sulfur trioxide - atoms
Sulfur trioxide – molar mass
Compound
SO3
Compound
Sodium Chloride
Molar mass (g/mol)
H2 O
Lithium Iodide
CO2
Calcium Oxide
C6H12O6
Sodium Phosphate
Fe2O3
Potassium Nitrate
Al2O3
Iron (III) oxide
Molar Mass (g/mol)
The molar mass is the direct conversion from moles to mass!!!!
Target 14: Convert moles to mass in grams (Show your work for full credit)
Aluminum satellite dishes are resistant to corrosion because the aluminum reacts with oxygen in the air
to form a coating of aluminum oxide (Al2O3). This tough, resistant coating prevents any further
corrosion. What is the mass in grams of 9.45 moles of Aluminum Oxide?
Step 1
Step 4
Step 2
Step 5
Step 3
Practice – Show your work for full credit.
1. What is the mass in grams of 6.44 moles of Sodium Chloride?
2. Find the mass in grams of 7.23 moles of Lithium Iodide.
3. What is the mass in grams of .56 moles of Calcium Oxide?
4. Find the mass in grams of 2.90 moles of Sodium Chloride.
Target 15 - Convert mass in grams to moles. (Page 299)
When iron is exposed to air, it corrodes to form red-brown rust. Rust is iron (III) oxide (Fe2O3). How
many moles of iron (III) oxide are contained in 92.2 grams of Fe2O3?
Step 1
Step 4
Step 2
Step 5
Step 3
Practice – show all work to receive full credit
1. How many moles of Sodium Chloride are contained in 62.4 grams of Sodium Chloride?
2. Find the number of moles in 24.6 grams of Carbon dioxide.
3. Calculate the number of moles in 69.2 grams of Dihydrogen monoxide.
4. How many moles of Sodium Phosphate are contained in 79.3 grams of Sodium Phosphate?
Target 16 – Convert grams of a substance to the number of representative particles.
A. In order to convert grams of a substance to the number of representative particles, you must convert grams to
moles, and then moles to representative particles.
How many molecules of H2O are in 3.44 grams of H2O?
Step 1
Step 4
Step 2
Step 5
Step 3
Practice – show all work to receive full credit
1. How many Molecules of Sodium Chloride are contained in 72.4 grams of Sodium Chloride?
2. Find the number of atoms that are in 24.6 grams of Neon.
3. Calculate the number of molecules that are in 69.2 grams of Dihydrogen monoxide.
4. How many atoms of Sodium are contained in 79.3 grams of Sodium?
Target 17 – Convert the number of Representative particles to grams.
A. In order to convert the number of representative particles to grams, you must convert to moles, and then grams.
How many grams of CO2 is equal to 4.45 x 1024 molecules of CO2?
Step 1
Step 4
Step 2
Step 5
Step 3
Practice – Show your work for full credit.
1. What is the mass in grams of 3.44 x 1026 molecules of Sodium Chloride?
2. Find the mass in grams of 5.23 x 1027 molecules of Lithium Iodide.
3. What is the mass in grams of 5.64 x 1022 molecules of Calcium Oxide?
4. Find the mass in grams of 2.90 x 1025 atoms of Sodium.
PART C - PERCENT COMPOSITION AND CHEMICAL FORMULAS
Target 18: Calculate the percent composition of a compound when given the
formula (page 305)
A. It is important to know which elements are in a compound and how many.
B. The formula will tell you this.
C. However, there is more information in a formula that chemists find useful.
D. Percent composition – The percent by mass of element in a compound.
E. Remember that a percent is a fraction of 100
Write the formula for percent composition here.
1. Determine the percent composition Potassium
chromate.
2. Determine the percent composition of Potassium
dichromate.
Target 19 - Calculate percent composition from mass data (page 306)
When a 13.60 gram sample of a compound containing only magnesium and oxygen is decomposed, 5.40
grams of oxygen is obtained. What is the percent composition of this compound?
Practice – show all work to receive full credit
1. When a 300.0 gram sample of a compound containing only Nitrogen and Oxygen is decomposed,
77.4 grams of Oxygen is obtained. What is the percent composition of this compound?
2. When a 12.51 gram sample of a compound containing only Magnesium and Nitrogen is
decomposed, 9.03 grams of Magnesium is obtained. What is the percent composition of this
compound?
3. When a 14.2 gram sample of Mercury (II) oxide is decomposed into its elements by heating, 13.2
grams of Hg is obtained. What is the percent composition of the compound?
4. A compound is formed when 9.03 grams of Magnesium combines completely with 3.48 grams of
Nitrogen. What is the percent composition of this compound?
Target 20: Determine the empirical formula when given the molecular formula
1. If you were cooking _______________– you would need 1 cup of rice and 2 cups of water.
2. This is the basic recipe for cooking rice.
3. If you wanted to cook ______________ the amount of rice, you would use this recipe and multiply all
ingredients by 2. Therefore adding 2 cups of rice and 4 cups of water.
4. This principle works in chemistry too.
5. Empirical formula – Formula that gives the _________________whole number ratio of elements in a
compound.
6. Molecular formula – Formula that gives the _____________ number of elements in a compound.
7. For example, glucose has the molecular formula of C6H12O6.
8. To find the Empirical formula for glucose, you would need to find the greatest common factor
(________) of all the subscripts in the compound.
9. The GCF for glucose is 6 – therefore you would divide all subscripts by 6 to obtain an Empirical
formula of CH2O.
10. Notice the ratio is 1:2:1 in both the _____________________formula and the empirical formula
 Questions
1. What is an empirical formula? ________________________________________
2. What is a molecular formula? _________________________________________
3. The molecular formula for Hydrogen Peroxide is H2O2. What is the empirical formula?
_________________________
4. The molecular formula for Benzene is C6H6. What is the empirical formula?
_________________________
5. The molecular formula for ethanoic acid is C2H4O2. What is the empirical formula?
_________________________
6. The molecular formula for methanal is CH2O. What is the empirical formula?
_________________________
7. Can the molecular formula and the empirical formula be the same? ____________
Save this for another day
Objective 21 – Determine the empirical formula of a compound when given the percent composition.
A. There are 4 steps for determining the empirical formula when given the percent composition.
1. Convert the percent composition of each substance to grams.
2. Convert the grams of each substance to moles (shortcut = divide by the molar mass of each substance)
3. Determine the smallest number of moles.
4. Divide the number of moles of each substance by the smallest number of moles.
5. Determine the closest whole number for each element – that will be the subscript.
Determine the Empirical formula of a compound that contains 88.8% Copper and 11.2% Oxygen.
Step 1
Step 2
Step 3
Step 4
Step 5
1. Determine the Empirical formula of a compound that contains 70.0% Iron and 30.0% Oxygen.
2. Determine the Empirical formula of a compound that contains 10.1% Carbon, 0.920% Hydrogen, and 89.1%
Chlorine.
3. Determine the Empirical formula of a compound that contains 12.6% Hydrogen, 37.5% Carbon, and 50.1%
Oxygen.
4. Determine the Empirical formula of a compound that contains 52.8% Aluminum and 47.1% Oxygen.
Objective 21 – Determine the empirical AND molecular formula of a mystery substance when given the percent
composition and molar mass.
A chemist thinks she has made a new compound. She measures the percent composition and gets the
following results: 47.43 % Molybdenum and 52.57% Chlorine. Calculate the empirical formula of the
compound? Calculate the molecular formula of the compound. (Molar mass = 606.57amu)
This is a different approach – save for later.
A compound of nitrogen and oxygen is analyzed, and a sample weighing 1.587 grams is found to contain
0.483 grams of N and 1.104 grams of O. What is the empirical formula of the compound?
See page 130 in chemistry text book.
Ask sartain or lewis for other sample problems - second example in book is too hard.