Unit 6 Mole and Stioch.
Unit 6 Starts
Tues:
Panther Drill Review Problem
5-10 min Review
Quiz
Early Finish = Word Search
Panther Drill
Potassium Chlorate reacts to form Potassium chloride
and oxygen gas. Write the equation for this
reaction, balance it, and state what type of reaction
it is.
Skeleton Equation: KClO3  KCl + O2
2
3
3
Balanced ____KClO

___
KCl
+
____O
3
2
Wednesday
PD= Converions
Modeling: How to us Dim Anaylisis
Practice
TODAY
Today: We will practice using dimensional
analysis to convert between units. This is a
review of what we did in
Panther Drill
Convert 5 feet into cm. 1 inch = 2.54 cm Set up
the conversions using dimensional analysis.
5ft x
12 in
1 ft
2.54 cm =
1 in
152.4 cm
Active Inspire Practice
Thurs
Panther Drill
Guess how many activity
Pairs will list ways items are quantified other
than by the each.
Notes Discussion on the mole
Exit ticket “Explain the mole is similar to a
dozen.”
Panther Drill
There are 50
TODAY
paperclips in a box 1. 1 more dimensional
analysis problem
and 20 boxes in a
2. Explain how to count
case. If I have
large numbers of
2750 paper clips
small items w/out
how many cases
counting them
individually
do I have?
3. Meet the Mole.
Get with your partner
Make a list of different units there are to count items.
EXAMPLES
Ream: 500 pieces of paper.
A gross: A gross of something = 144 of an item
Hint: How are things sold in the
supermarket.
Active inspire
List our lists
1 Intro
We have seen how much easier it is to count
small items such as paper clips by a larger unit
rather than by the each.
That was easy compared to if you had to count
the number of atoms of aluminum in a paper
clip.
2 Intro
Chemist often have to find out how many atoms
or particles of an element or compound are in
a sample. This would be nearly impossible
with out a unit that would count a very small
things w/ out counting each particle
individually.
Chemists use the Mole
NO not either of these
3 IMPORTANT!!
A mole or (mol) is the SI or scientific unit for
counting particles, atoms, or molecules.
The mole was defined in 1811 by an Italian scientist
and lawyer named Avogadro. He figured out that
there was 602,213,670,000,000,000,000,000
particles of anything in 1 mole of that item.
We use scientific notation = 6.02x 1023
This is called Avogadro’s number
4
Look at the test tubes being past around you will
see that you can have moles of different kinds
of particles.
Tube 1 has 1 mole of copper atoms
Tube 2 has 1 mole of water molecules
Tube 3 has 1 mole of salt molecules
Beaker has 1 mole of sugar molecules
What do you notice about the moles of the
items, how are they different?
5
Think about it this way
A mole of sugar molecules can look larger than a
mole of salt molecules (even though they both
contain 6.02x 1023 particles) because the
molecules of sugar are larger than a salt
molecules.
Just like a dozen marbles looks
larger than a dozen than a dozen
pennies, but the each have 12
items in them.
EXIT TICKET
NAME:
Explain the mole is similar to a dozen.
Monday
Panther Drill
In your own words define a mole as it is used in
chemistry.
What’s in a Mole
Remember the mole is the # of particles in a
sample.
Avogadro's # says there are 6.02 x 1023 particles
of any thing in a mole of a sample being
measures
There are 3 different representative particles
that a mole can count: Atoms, Molecules, and
Formula units
In an element (H,Cl, Zn ect) it represents atoms
In a molecular compound such as water,
sucrose, and carbon dioxide, the mole counts
molecules.
In an Ionic Compound like NaCl, or Magnesium
Oxide, the mole counts formula units
What is the representative particle in the
following?
1.
2.
3.
4.
5.
LiCl Formula Units
C12H22O11 Molecules
BeH2 Formula Units
Mg ATOMS
PCl5 Molecules
Conversion Cheat Sheet
On the index card provided or somewhere you won’t
lose it write down the following:
You can use this when doing
conversions
Side 2 of Index Card
Finding the number of moles
# of Moles = # of particles X ___1 mole
__
6.02 X 1023 particles
.
Side 1 of Index Card
Finding the number of particles
# of Particles = # moles X
6.02 X 1023 particles
1 mole
Panther Drill
What is the representative particle being counted by
the following:
1. NaCl
2. CO2
3. Fe
4. H2SO4
Conversion moles to particles
Convert 3.50 moles of Sucrose to # of particles
3.50 moles x X
DO THE MATH:
2.11 x 1024
6.02 X 1023 particles =
1 mole
Conversion (Particles to Moles)
Convert 4.5 x 1024 atoms of Iron to moles of iron
What Conversion factor?
# of Moles = # of particles X 1 mole
___
6.02 X 1023 particles
.
Moles = 4.5 x 1024 atoms X
DO THE MATH:
7.48 moles Fe
1 mole
___
6.02 X 1023 atoms
.
You practice now
You and your partner practice now
Partner A
Partner B
1. 2.5 moles of Zn to # 1. 4.0 moles of CO2
atoms
to # molecules
2. 2.9 x 1024 formula
units of NaCl to
moles
2. 7.2 x 1023 formula
units of Li2S to
moles
Tuesday
Panther Drill
1) Convert 3.50 moles of Salt to # of particles
2) Which types of particles are you counting
(atoms, molecules or formula units) in the
compound salt?
Work on some mole conversions on
your own
Get a WS and complete all 5 problems
Examples
Moles = 4.5 x 1024 atoms X 1 mole
_ = 7.48 moles Fe
6.02 X 1023 atoms
# Particles: 3.50 moles X 6.02 X 1023 part. = 2.11 x 1024
1 mole
molecules
Moles and Mass
Panther Drill
If 1 dozen eggs weighs 2.3 pounds, determine how
much 5.5 dozen weigh.
5.5 doz
1
X 2.3 lb = 5.5 X 2.3 lbs =
1 doz
12.65 lbs
Mass and the mole in single elements
A mole always contains the same number of particles;
but moles of different substances have different
masses.
Think about it like this: A mole is like a dozen.
A dozen bowling balls would have a different mass
than a dozen eggs, but each one still has 12 items in
it.
Lets look at the element Carbon
1 mole of Carbon = 6.02 x 1023 atoms
Carbon has an molar (atomic)mass
of 12.01 g
12
C
Carbon
12.01
The mass of 1 mole of a substance = the molar mass
**The mass of 1 mole of an element can be found
on the periodic table
Converting from # of moles to mass
Lets look at a dozen jellybeans
1 dozen jellybeans = 35 grams
THIS BECOMES OUR CONVERSION FACTOR
How many grams are there in 5 dozen jelly beans?
5 dz Jellybeans
175
35 grams
= __________
g
1 dz jelly beans
Converting From Moles to Mass
The mass of 1 mole of carbon = 12.01 g
How many grams are there in 8 moles of carbon?
8 moles of C x
12.01 g C
1 mol C
96.08
=____________
g Cu
Moles to Mass (2)
The mass of 1 mole of copper = 63.546 g
How many grams in 4 moles of copper:
262.18
4 mol Cu = 65.546 g Cu =____________
g Cu
1 mol Cu
Converting Mass to Moles
You have 7.6 Grams of Boron (Atomic/Molar Mass 10.81)
Convert grams of Boron to moles of Boron
Conversion factor: 1 mole of boron = 10.81 grams
How would you set up the conversion fraction?
0.703
1 mol B
7.6 g B
X
= ________mol
B
10.81 g B
1
You Try
Partner A and B
PARTNER A
How many moles are in 15 grams of lithium?
Partner B
How many grams are in 2.4 moles of sulfur?
Each student do their own problem and then
explain how they got the answer to their
partner
Partner A
How many moles are in 15 grams of lithium?
(molar mass of lithium is 6.94 g/mole)
15 grams Li x 1 mole =
6.94 grams
2.16 moles
15/7 moles Li
Partner B
How many grams are in 2.4 moles of sulfur?
molar mass of sulfur is 32 g/ mole
32.065 grams S
2.4 moles x
1mole S
76.956 g S
Practice Moles to Grams of Atoms
How many moles are in 22 grams of argon?
How many grams are in 88.1 moles of magnesium?
How many moles are in 2.3 grams of phosphorus?
How many grams are in 11.9 moles of chromium?
How many moles are in 9.8 grams of calcium?
Practice Moles to Grams of Atoms
How many moles are in 22 grams of argon?
How many grams are in 88.1 moles of magnesium?
How many moles are in 2.3 grams of phosphorus?
How many grams are in 11.9 moles of chromium?
How many moles are in 9.8 grams of calcium?
MONDAY
Panther Drill
How many moles are in 198.6 grams of potassium?
198.6g K x 1mol . ___________
moles K
5.08
39.1 g K
How many grams are in 12.3 moles of nitrogen?
172.32
12.3 mol N 14.01 g N ___________
g N
1 mol N
Converting Grams to Moles to Particles
2 ways to do this
1. Convert from grams to moles then separately
convert from moles to particles.
Example: Convert 41.7 grams of boron to atoms of
Boron
1 mole B
3.86 mole B
a) 41.7 g B x 10.81 g B
= __________
b) 3.86 mol B x
6.02 x 1023 atoms B
1 mole B
24
2.32x
10
=_________ atoms B
Converting Grams to Moles to Particles
2. Do all the conversions in the same equation
Example: Convert 41.7 grams of boron to atoms of
Boron
6.02 x 1023 atoms B
1
mole
B
a) 41.7 g B x
= # atoms B
x
1 mole B
10.81 g B
6.02x1023
41.7 x
10.81
24
2.32x
10
=_________ atoms B
Try This One
How many atoms are in 2.13 grams of Helium
INSERT ACTIVEINSPIRE HERE
Vitamin Lab Activity
You need to get your partner assignments
You need to get a lab sheet for your groups and
get the material on the lab sheet.
Get to work
Tuesday
Continue lab activity and turn in at the end of
the period.
Panther Drill
Create a simple flow
chart that shows the
process of converting
mass to moles, to
atoms of an element.
For each step, make
sure to show the
conversion fractions
you would use to do
that step
Examples of flow chart
outline
Continue w/ Vitamin lab activity
Micrograms to grams
2mcg Mg x
1 gram
1,000,000 mcg
Wednesday
P-drill
Finish Vitamin Lab and turn in at end of the
period.
Students finishing early will do extra credit
assignment converting grams to moles.
Exit ticket thumbs up down on grams-molesparticle converting of an element
Panther Drill (Review Material)
1. Which of the following elements has three valence
electrons?
a) lithium
b) boron
c) nitrogen
d) more than one of the above
2. Which of the following is not an acid?
a) HNO3
b) CH3COOH
c) H2SO4
d) All of these are acids
Thursday
Panther Drill
Find the mass of 1 mole of the following:
Carbon:
12.01
Phosphorus:
Iron:
30.97
55.85
From the periodic table we get 16.00
Oxygen Gas:
Amu, but Oxygen is diatomic so in the
Real word it would be 16 x 2 = 32.00
Formula Weight or Mass
Formula Weight is the total of all the atomic masses
for each element in the formula for a compound.
Formula mass, Molar mass, and Formula Weight are
the same thing.
The formula mass or weight is like the atomic mass of
a compound.
The mass of 1 mole of a compound = the formula
mass or weight
Example
Determine the formula mass of 1 mole of Magnesium
Chloride?
1. Write the chemical formula. (if it is not given)
Remember to “criss-cross” the charges to get the
subscripts. (**Signs Drop off)
Magnesium Chloride
Mg2+ Cl-1 = MgCl2
2. Determine the atomic mass for each element.
Mg= 24.31 g/mol ; Cl=35.45 g/mol
3. Look to see how many of each element there are
in the formula. Mg = 1 atom ; Cl = 2 atoms
Example (cont)
4. Multiply the number of atoms of each element in
the formula by the atomic mass of each element.
(Mg) 1 x 24.31 g = 24.31 g
(Cl) 2 x 35.45 g = 70.90 g
5. Add up the results:
24.31 g + 70.90 g = 95.21 g
1 mole of MgCl2 = 95.21 g
The formula mass of MgCl2 = 95.21 g
Learning Check
How many grams in 1 mole
A. 1 mole of K2O
= ______g
B. 1 mole of antacid Al(OH)3 = ______g
70
Solution
A. 1 mole of K2O
K: 2 x 39.1g/mol = 78.2g
O: 1 x 16g/mol =
16 g
78.2 + 16
=94.2 g K2O
B. 1 mole of antacid Al(OH)3
Al: 1 x 27.0 g/mole = 27
O: 3x 16.0 g/mole = 48
H: 3 x 1.01 g/mole = 3.03
27 + 48 + 3.03
= 78.02 g Al(OH)3
71
Practice
Partner A:
Molar mass of Na3P
Molar Mass of CH4O3S (Methanesulfonic acid)
Partner B
Molar mass of AlCl3
Molar Mass of C6H12O6
Calculate Molar Mass
Complete the 5 problems on the 1/2 page WS
and turn them in in the basket. You need to
work by your self and you have 10 to 15 min
to complete.
Write the Formula Mass for the
following and Turn in when completed
1.
2.
3.
4.
5.
6.
NaF
KGa
Diphosphorus trioxide
LiS2
Diphosphorus hexachlorine
Al2O3
Write the Formula Mass for the
following and Turn in when completed
1.
2.
3.
4.
5.
6.
NaF
KGa
Diphosphorus trioxide
LiS2
Diphosphorus hexachlorine
Al2O3
EXIT TICKET
Prozac, C17H18F3NO, is a widely used antidepressant
that inhibits the uptake of serotonin by the brain. It
has a molar mass of
1) 40.0 g/mole
2) 262 g/mole
3) 309 g/mole
76
Friday
Students will learn to convert between grams
and moles of compounds
Students will work on a comprehensive work
sheet that covers formula mass and
converting from formula mass of a compound
to moles of a compound.
Individual work will take all period
Panther Drill
Prozac, C17H18F3NO, is a widely used antidepressant
that inhibits the uptake of serotonin by the brain. It
has a molar mass of___________________?
79
Solution
Prozac, C17H18F3NO, is a widely used antidepressant that
inhibits the uptake of serotonin by the brain. It has a
molar mass of
17C x (12.01)= 204.17
1N (14.01) =
18.18
57.00
14.01
+ 1 O (16.0) =
16.00
18H (1.01) =
3F (19.0) =
309 .36
309 .36 g/mole
of Prozac
80
Converting between Moles and Mass of a
compound.
Done the same way as w/ elements
Same conversion Fractions but w/ compounds not
elements and molar mass instead of atomic mass
Grams x 1 mole of compound = # moles compound
molar mass of compound
Converting between Moles and Mass and moles
to mass of a compound.
1) See what the problem gives you and see what it is
asking for.
2) Determine the chemical formula & calculate the
molar mass
3) Do the math
Mass to moles: Molar mass on the bottom of
the fraction and divide.
Moles to mass: molar mass on top and multiply
REMEMBER WHEN GOING MASS-MOLES WE
DON’T NEED 6.02 X 10
23
Converting between Moles and Mass of
a compound.
EXAMPLE Mass to Moles
How many moles are in 198 grams of water?
Step 1: See what you are given in the problem and
what it wants you to answer.
198 grams H2O ; Wants Moles of H2O
Step 2: Determine the chemical formula & calculate
the molar mass
H: 2 x 1.08
2.16 + 16
O: 1 x 16.0
Molar Mass = 18.16 g/mole of water
Converting between Moles and Mass
of a compound
3. Multiply the mass you are given by 1 mole over the molar
mass of water. Then simplify, the fraction that is left (divide
the top number by the bottom. 198 g divided by 18.16 g =
moles water)
=
198 g of water x 1 mole water = 198
18.16 g water
18.16
10.93 mole
= _______
Water
You Try
How many moles are in the 171.16 grams of
Lithium Chloride?
Converting between Moles and Mass
of a compound.
EXAMPLE Moles to Mass
What is the mass of 4.5 moles of CO2
Step 1: See what you are given in the problem and
determine the chemical formula of the compound.
CO2
Step 2: Calculate the molar mass
C x 1 = 1x 12.01 g
12.01 + 16
O x 2 = 2 x 16 g
Molar Mass = 44.01 g/mole of CO2
Moles to Mass (cont)
EXAMPLE Moles to Mass
Step 3: Set up the equation by multiplying the # of
moles given by the molar mass over 1 mole.
44.01 gramsCO2 = 4.5 x 44.01
4.5 moles CO2 x
1 mole CO2
= 198.05 mol CO2
Partner A / B
Partner A:
You are given 5.46 moles of MgO how many grams
do you have?
Partner B:
You need to convert 164.4 grams of CaCl2 to moles.
When you are finished explain to each other how
you got your answers and sign off on each others
work
Fri
Panther Drill
Organize your materials for your open notes quiz.
Ask any questions you have.
Study
If the class is loud we will immediately start the quiz.
After you turn your quiz in to me at the desk, pick up
a practicing percentages problem set.
Turn in panther drill from Tuesday, and any other
work still out in the basket on the table.
Weds
Mon and Tues = Sub
Panther Drill % review
1. Mary has a monthly salary of $1200. She
spends $280 per month on food. What
percent of her monthly salary does she
spend on food?
280/1200 x 100 = 23.33%
2. What is 98.3% of 23?
98.3%/100 .983 x 23 = 22.61
No Panther Drill for Monday
WEDS CLASS WILL MEET IN MEDIA CENTER
Thursday
Percent Practice
Panther Drill
Convert the following to fractions:
1. 37% 37
100
2. .983
98.3/100
Definition
• Percent can be defined as “of
one hundred.”
of
100
Percents Have Equivalents in
Decimals and Fractions
Percent
Fraction
Decimal Fraction Simplified
1
20
20% =.20 = 100 = 5
Always simplify fraction to
lowest terms!!!
Remember These Equivalent Fractions
1
2
1
4
3
4
1
3
= 50%
= 25%
= 75%
= 33.3%
2
3
1
5
2
5
3
5
= 66.6%
= 20%
= 40%
= 60%
How to Find the Percent of a
Whole Number
• The first thing to remember is “of”
means multiply in mathematics.
of = x
How to Find the Percent of a
Whole Number
•
Step 1 - When you see a percent problem
you know when you read “of” in the
problem you multiply.
25% xof 200
Copyright © 2000 by Monica Yuskaitis
How to Find the Percent of a Whole
Number
•
Step 2 – Change your percent to a
decimal and then move it two places
to the left.
. 25%
. x 200
Copyright © 2000 by Monica Yuskaitis
How to Find the Percent of a Whole
Number
•
Step 3 – Multiply just like a regular
decimal multiplication problem.
200
x . 25
50.00
Is/of = %/100
IS
OF
=
IS x 100 = OF x %
%
100
Cross
Multiple
Solve for
what ever
is unknown
Is/of (cont)
26 is what % of 34?
Step 1) See what you are
given
is = 26
of = 34
% = ????
Step 2: Set up: is/of = %/100
26 =
X
34
100
Step 3: Isolate
unknown and solve:
Cross multiply:
34X = 2600
Divide to isolate
unknown
34X = 2600
34
X = 76.47
Quick Practice A/B Partner
Convert these to
decimals:
1) 21% .21
2) 6/8 .75
3) 66% .66
Convert these to
fractions:
1) 79% 79/100
2) .55 55/100 or 11/20
3) 33.3% 33/100
Or 1/3
Quick Practice 2
Convert these to %:
1)
2)
3)
4)
5)
2/5 40%
2/10 20%
.5934 59.34%
.026 2.6%
1.64 164%
Practice.
Panther Drill
Example 1. Homer has a box of assorted
doughnuts. 3 of these doughnuts are
chocolate. What percentage of Homer's doughnuts
are chocolate? (note, we are talking about total
number, not mass, in this case.)
Solution
number of chocolate doughnuts
% of doughnuts that are chocolate = ------------- x 100
Total # doughnuts
3
% of doughnuts that are chocolate = ----------- x 100
12
.25 x 100 =
25% Chocolate
Percent composition
As we briefly discussed in the beginning of the year,
percent composition is the amount of each element
in (in %) a compound. Also called mass percent of a
compound.
Mass % = mass of element in 1 mole of a compound X 100
molar mass of compound
Mass % of H and O in Water
What is the % composition of Oxygen in water?
Molar Mass H2O: 18.02 g
Mass of O in H2O: 16 g
Mass% O = (16 / 18.02) X 100
Mass % O = 0.8879 X 100
Mass % O = 88.79
Oxygen accounts for 88.79% of the mass of a
molecule of water
Mass % of H and O in Water
What is the % composition of Hydrogen in water?
Molar Mass H2O: 18.02 g
Mass of H in H2O: [2 x 1.01] = 2.02 g
Mass% O = (2.02/ 18.02) X 100
Mass % O = 0.1121 X 100
Mass % O = 11.21 %
Hydrogen accounts for 11.21% of the mass of a
molecule of water
Lets do a problem together
What is the mass % of sodium in NaCl?
Partner A /B
Partner A: Determine the mass % of Carbon and
Hydrogen in CH4.
Partner B: Determine the mass % of Phosphorus
and Oxygen in PO3
Sign off on and check your partners work
Panther Drill
Do this somewhere in your notes, I will be around to
check it.
What is the Mass% of each element in Sucrose:
C12H22O11
Panther Drill
1. How does ionization energy and atomic radius
change as move to the right across and down the
periodic table.
IE: As you move across a period, first ionization
energy increases
As you move down a group, first ionization energy
decreases.
AR: As you move down a group, atomic radius
increases.
As you move left to right across a period, atomic
radius decreases.
Work on Lab report
DUE WEDNESDAY at
the beginning of class
Choices
• If you finish early, either work on the
Chapter 11, pre-assignment OR use
your knowledge of elements and the
periodic table to complete the “Its
Elementary” Chemistry March
Madness assignment.
Real Bracket
Its Elementary Bracket Rules
Round #
1. The element discovered first wins the
game and moves on.
2. Ionization E the highest wins the game
and moves on.
3. Element in the group w/ the highest
group number wins and moves on.
4. Atomic Radius the highest wins the game
and moves on.
Its Elementary Bracket Rules
Semi-finals (final 4):
Solve the riddles to determine the two
elements that will compete for the
championship.
Finals:
Fill in the blank on the your insruction
sheet to determine the winner
Chap 11 Pre-Assignment
Use the text book to complete the
packet.
Panther Drill
1. List 3 things that you can observe that tell you a
chemical reaction or a chemical change has
occurred.
a. New substances are formed
b. It burns (light)
c. Temperature changes without adding
or removing heat
d. It bubbles (makes a gas)
e. It changes color
f. It forms a precipitate
Parts of Chemical
SO3(g) + H2O(l) ---> H2SO4 (aq)
Reactants
Products
Yields
State of
Compound
State of
Compound
Real World Connection
SO3(g) + H2O(l) ---> H2SO4 (aq)
Above is the equation for acid rain
This results from the release from industry and natural
sources into the atmosphere.
The Sulfur trioxide is mixed into the atmosphere when it
rain the Sulfur trioxide mixes with rain water as it
condensates from the atmosphere and falls to earth
as Sulfuric acid.
Demo Lab
1. Was this a chemical rxn? How Could you tell?
2. If the word equation is aqueous Hydrochloric acid
and zinc metal mixes to produce Zinc chloride
powder, water and Hydrogen gas. What is the
symbol equation?
3. Now balance the equation.
4. Would there be more H gas produced if I kept
adding HCl until the test tube was 80% full? Why
or Why not.
Panther Drill
What “LAWs” tells us that equations must be
balanced with = amounts on each side of the
yield sign? Be specific.
Law of Conservation of Mass
(Mass doesn't change)
Law of Conservation of Matter
(Moles don’t change)
STOICHIOMETRY
What is stoichiometry?
• Stoichiometry is the quantitative
study of reactants and products
in a chemical reaction.
Panther Drill
In your own words define a ratio, and give an
example.
What You Should Expect
• Given : Amount of reactants
• Question: how much of products can be
formed.
• Example
• 2 A + 2B
3C
• Given 20.0 grams of A and sufficient B, how
many grams of C can be produced?
What do you need?
i.
ii.
iii.
iv.
You will need to use
molar ratios,
molar masses,
balancing and interpreting equations, and
conversions between grams and moles.
Note: This type of problem is often called "mass-mass."
Steps Involved in Solving Mass-Mass
Stoichiometry Problems
• Balance the chemical equation correctly
• Using the molar mass of the given substance,
convert the mass given to moles.
• Construct a molar proportion (two molar
ratios set equal to each other)
• Using the molar mass of the unknown
substance, convert the moles just calculated
to mass.
Mole Ratios
A mole ratio converts moles of
one compound in a balanced
chemical equation into moles
of another compound.
Example
Reaction between magnesium and oxygen to form
magnesium oxide. ( fireworks)
2 Mg(s) + O2(g)
Mole Ratios:
2
:
1
2 MgO(s)
:
2
Practice Problems
1) N2 + 3 H2 ---> 2 NH3
Write the mole ratios for N2 to H2 and NH3
to H2.
2) A can of butane lighter fluid contains
1.20 moles of butane (C4H10). Calculate
the number of moles of carbon dioxide
given off when this butane is burned.
Panther Drill
What is the ratio between male and female
students in the picture: write all possible
ratios, then write it out like a chemical
equation.
Panther Drill answers
1) 17 total students, 7 females, 10 males.
Males to females = 10 to 7 or 10 males
7 female
Females to males: 7 to 10 or 7 females
10 males
Males to total: 10 : 17 10 males/17 students
Females to total 7 : 17 , 7 females/17students
Bal Equat: 10 males + 7 females  Class
Ratios
Ratios can be expressed in many ways:
3:5, 3 to 5 or 3/5
We are going to be mainly concerned with ratios
displayed as fractions
The ratio of A to B = A .
B
**** The first item (number) always is the
numerator, the last is the denominator. ***
Ratios
1) It takes 2 eggs ¼ onion, 12 slices of jalapenos and 1
slice of cheese to make Mr P.’s favorite omelet
what are the total ratio and the ratio of each
ingredient to the end(fraction form) result.
Total: 2eggs : ¼onion: 12jalapeno: 1slice: 1omelet
2 eggs/1omelet
¼ onion/1 omelet
12 slices jalapeno/ 1 omelet
1 slice of cheese/ 1 omelet.
Is this a problem a good example to use in
chemistry? Why?
Example
Panther Drill
Balance the equation and write down the ratios
of each reactant to the product
2
1
2
_____H2 + _____O2  _____H2O
2 mol H2 : 2 mole H2O -- 1:1
1 mol O2 : 2 mole H2O
Panther Drill
Balance the equations and write the mole ratios
of each reactant to each product (Should be 4
ratios total)
_____NH3 + _____O2  _____NO + _____H2O
NH3 /NO
NH3 / H2O
O2 /NO
O2 / H2O
Set this chart up in notebook
Steps
1
2
3
4
5
Problem 1
Problem 2
Solving Mole-Mass or Mass to Mass Problems. List these
in your table next to the number
1. Identify what is given and what the problem is
asking for.
2. Write and balance the chemical equation
correctly. (depending on what is required)
** 1 and 2 can be in either order
1. Using the molar mass of the given substance,
convert the mass given to moles (if needed)
2. Construct a molar proportion equation (w/ one
or more molar ratios in conversion fraction form)
3. Convert the moles just calculated to mass
wanted by the problem.
Problem
If you have 13 moles of oxygen and excess Aluminum,
how many grams Aluminum Oxide will be formed?
1)
13
mol
O
2
GIVEN:_____________
Grams Al2O3
NEEDED:______________
2) Write and or balance the chemical equation
correctly.
4
3
2 Al O
______Al
+ _____O

_____
2
2 3
3) Using the molar mass of the given substance,
convert the mass given to moles (if needed)
NOT NEEDED IN THIS PROBLEM BECAUSE YOU
HAVE BEEN GIVEN MOLES, OFTEN YOU WILL
BE GIVEN MASS OF A SUBSTANCE!!!!
4) Construct a molar ratio equation (w/ one or more molar
ratios in conversion fraction form) & do the math
Mole ratio = 3 moles O2 : 2 moles of Al2O3
Keeping in mind we have oxygen and need to find
Al2O3 , what goes in the numerator and what goes
in the denominator?
2 moles of Al2O3
3 moles of O2
13 moles of O2
X
2 moles of Al2O3
3 moles of O2
=
8.67mol Al2O3
5) Convert the moles just calculated to mass wanted
by the problem (using molar mass)
Atomic masses:
O = 16, Al = 27
Compound: Al2O3
Molar Mass = (27 x 2) + (16 x 3) =
X
8.67mol Al2O3
102 g= per mole of Al2O3
102 g Al2O3
1 mole Al2O3
884.34 g Al2O3
Create a table in your notes like is on
the next slide
Set this chart up in notebook
Steps
1
2
3
4
5
Problem 1
Problem 2
Solving Mole-Mass or Mass to Mass Problems. List these
in your table next to the number
1. Identify what is given and what the problem is
asking for.
Have: “have, will react, are consumed…”
Need: “are produced, will be made, yields…”
2. Write and balance the chemical equation
correctly. (depending on what is required)
Solving Mole-Mass or Mass to Mass Problems. List these
in your table next to the number
3. Using the molar mass of the given substance,
convert the mass given to moles (needed if you
are given grams, not needed if given moles)
4. Construct a molar proportion equation (w/ one
or more molar ratios in conversion fraction form)
3 mol N2 / 1 mole Mg
5. Convert the moles just calculated to mass
wanted by the problem.
Problem
If you have 13 moles of oxygen and excess Aluminum,
how many grams Aluminum Oxide will be formed?
1)
13
mol
O
2
GIVEN:_____________
Grams Al2O3
NEEDED:______________
2) Write and or balance the chemical equation
correctly.
4
3
2 Al O
______Al
+ _____O

_____
2
2 3
3) Using the molar mass of the given substance,
convert the mass given to moles (if needed)
NOT NEEDED IN THIS PROBLEM BECAUSE YOU
HAVE BEEN GIVEN MOLES, OFTEN YOU WILL
BE GIVEN MASS OF A SUBSTANCE!!!!
4) Construct a molar ratio equation (w/ one or more
molar ratios in conversion fraction form)
Mole ratio = 3 moles O2 : 2 moles of Al2O3
Keeping in mind we have oxygen and need to find
Al2O3 , what goes in the numerator and what goes
in the denominator?
2 moles of Al2O3
3 moles of O2
13 moles of O2
X
2 moles of Al2O3
3 moles of O2
=
8.67mol Al2O3
5) Convert the moles just calculated to mass wanted
by the problem (using molar mass)
Atomic masses:
O = 16, Al = 27
Compound: Al2O3
Molar Mass = (27 x 2) + (16 x 3) =
X
8.67mol Al2O3
102 g= per mole of Al2O3
102 g Al2O3
1 mole Al2O3
884.34 g Al2O3
Column #2 Mole-Mass Problem You Try
• Problem : 1.50 mol of KClO3
decomposes. How many grams of
O2 will be produced?
[k = 39, Cl = 35.5, O = 16]
2 KClO3
2 KCl + 3 O2
Steps…Get Your Correct Answer
• Is equation balanced?
YES
• What do you have, what do you need
1.50 mol of KClO3
grams of O2
• Use mole ratio 3 mol O2 / 2 mol KClO3
• Get the answer in moles
• Convert to grams using molar mass
O2 = 32
REMEMBER
If you are given a mass in the problem, you
will need to convert this to moles first.
Ok?
Mass reactant to Mass Products
Given the reaction
__Mg3N2 + __H2O ___MgO + ___ NH3
If 125 grams of MgO is produced, how much Mg3N2
was required in the reactants. Assume you have
plenty (excess) water.
What are the words that tell you what you have and
what you need?
Panther Drill
Complete the handout on your desk, it is eerily
similar to the one we did last
Thursday/Friday!!!
A/B Partners
1. Get w/ a partner, If there is an odd # I will be
a partner.
2. 1 Person do problem A, 1 Person do problem
B. BY YOURSELVES!!!!!
3. When both are FINISHED. Each partner will
explain their problem to the other STEP BY
STEP.
4. Sign off on each others work and let me see
it.
Partner A and B
For the reaction 2Na + Cl2  2NaCl, how many
grams of sodium chloride can be produced
from 500. g each of sodium?
For the reaction 2Na + Cl2  2NaCl, how many
grams of sodium chloride can be produced
from 500. g each of chlorine?
Partner A and B
For the reaction 2Na + Cl2  2NaCl, how many
grams of sodium chloride can be produced
from 500. g each of sodium?
For the reaction 2Na + Cl2  2NaCl, how many
grams of sodium chloride can be produced
from 500. g each of chlorine?
3)
4)
5)
6)
7)
____ P4 + ____ O2  ____ P2O3_________________
____ RbNO3 + ____ BeF2  ____ Be(NO3)2 + ____ RbF_________________
____ AgNO3 + ____ Cu  ____ Cu(NO3)2 + ____ Ag_________________
____ CF4 + ____ Br2  ____ CBr4 + ____ F2_________________
____ HCN + ____ CuSO4  ____ H2SO4 + ____ Cu(CN
Using the unbalanced equation:
__CaC2 + __H2O  __C2H2 + __Ca(OH) 2.
If 15 grams of C2H2 are produced, how much
water will be needed in the reactants?
Panther Drill Chem 4-14
Balance these equations
____C6H12O6 + ____O2  ___CO2 + ____H2O
1
6
6
6
___ GaBr3 + ___ Na2SO3  ___ Ga2(SO3)3 + ___ NaBr
2
3
1
6
Panther Drill 4/15
What is the % of Sodium in salt?
Mass % = mass of element in 1 mole of a compound X 100
molar mass of compound
% = atomic mass of sodium X 100
molar mass salt
= 23 g X 100 =
39.32 %
58.5 g
Practice
Determine the % composition of the following:
1. % Cl in NaCl
2. % H in C6H12O6
3. % Al in Al2O3
Practice
Determine the % composition of the following:
1. % Cl in NaCl
2. % H in C6H12O6
3. % Al in Al2O3