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Page Table of contents
1
Stoichiometry
1
Stoichiometry.
Standard 3
Ms. Siddall
Stoichiometry
elements
formulas
equations
The Mole
Mass/volume/
particles
conversions
1
The periodic table



The periodic table displays all elements
Symbols on the left represent metals
Symbols on the right represent non-metals
metals
Non-metals
Separation line
The periodic Table



2
The periodic table displays
all elements
Symbols on the left
represent metals
Symbols on the right
represent non-metals
3
Summary 1

Identify the following elements as metals
or non-metals:
1.
2.
3.
4.
5.
6.
Copper
Chlorine
Carbon
Sodium
Calcium
Hydrogen
The periodic Table
Summary 1: Identify the
following elements as
metals or non-metals



2
The periodic table displays
all elements
Symbols on the left
represent metals
Symbols on the right
represent non-metals
3
Symbols

Each chemical symbol on the periodic
table represents an element



chlorine = Cl
sodium = Na
Symbols written together represent a
compound

NaCl = a sodium atom combined with a chlorine
atom
The periodic Table
Summary 1: Identify the
following elements as
metals or non-metals
Summary 2:



The periodic table displays all
elements
Symbols on the left represent
metals
Symbols on the right represent
non-metals
symbols
Each chemical symbol on the
periodic table represents an element
chlorine = Cl
2
3
Notes…
Summaries…
4
5
Summary 2

Define the following words
1.
2.
3.
4.

Element:
Atom:
Compound:
Chemical formula:
Describe the similarities
and differences between
an atom and an element
Compounds

Covalent compound: non-metal atoms
combine to form molecules


Ionic compound: metal and non-metal atoms
combine to form formula units


e.x. H2O and CO2
e.x. NaCl, CuSO4
chemical formula: a combination of symbols
and numbers that describe the amount and type
and of atoms that form a compound.
Summary 3

Identify the following compounds as
ionic or covalent
1.
2.
3.
4.
CuSO4
NaCl
CO2
H2O
Anatomy of a chemical formula
CuSO4(aq)
Atomic symbols describe the type of atoms
in the compound
(copper, sulfur, oxygen)
subscript numbers describe the number of
atoms in the compound
(1 copper, 1 sulfur, 4 oxygen)
subscript letters describe the physical state
of the compound (aqueous)
Summary 4
Na2O(s)
In the above formula:
1. How many sodium atoms?
2. How many oxygen atoms?
3. What is the physical state?
4. Is the compound ionic or covalent?
Standard 3a: describing chemical reactions
An equation describes a chemical reaction or
a physical change
 Reactants: chemicals that react
 Products: chemicals that are formed
 e.x. sodium + oxygen  sodium oxide
Na(s) + O2(g)  Na2O(s)
reactants
product
Summary 5
Pb(NO3)3(aq) + KI(aq)  KNO3(aq) + PbI3(s)



Label the reactants and the products in the
reaction above
Are the reactants and products covalent or ionic?
How many oxygen atoms are in the compound
Pb(NO3)3?
Symbols describing chemical
reactions
Copy table 11.1 (page 323)
Summary 6
1.
What do the following symbols mean?



2.
(l)
(aq)

Pb(NO3)3(aq) + KI(aq)  KNO3(aq) + PbI3(s)

Which compound is solid?
Balancing chemical equations
The Law of Conservation of Matter: Matter
cannot be created or destroyed.

For chemical equations: The total number of
each type of atom must be the same before
and after the reaction
Thou shall not create
or destroy matter
example

Sodium reacts with oxygen to produce
sodium oxide
Na(s) + O2(g)  Na2O(s)



How many sodium atoms react? 1
How many sodium atoms are in the
product? 2
This violates the law of conservation of
matter!
Summary 7
NaI(s) + Cl2(g)  NaCl(s) + I2(s)
Count the number of
Count the number of
atoms on the reactants atoms on the products
side
side
Sodium ____
Sodium ____
Iodine ____
Iodine ____
Chlorine ____
Chlorine ____
Does this equation obey the law of
conservation of matter?
Example:
4 Na(s) + O2(g)  2 Na2O(s)
SUBSCRIPTS CAN NOT CHANGE!

Coefficients are used to balance the equation

number of atoms or formulas needed in
the reaction. These apply to the entire
formula (all the atoms)
4Na = 4 sodium atoms

2Na2O = 4 sodium atoms and 2 oxygen atoms

Summary 8
2Cu(s) + O2(g)  2CuO(s)
Count the number of
Count the number of
atoms on the reactants atoms on the products
side
side
copper ____
copper ____
Oxygen ____
Oxygen ____
Does this equation obey the law of
conservation of matter?
Rules of Balancing Equations
1.
2.
Write the equation using
correct formulas. You may
NOT change the formula in any
way.
Balance the equation using
coefficients
Balancing example:
sodium and oxygen react to form sodium oxide
Na + O2  Na2O
Take atomic inventory: (you must obey the Law
of Conservation of Matter)
Reactants:
Na
O
1
2
Products:
Na
O
2
1
Problem: begin with 2 oxygen atoms but end with only 1
This breaks the law of conservation of matter.
Na + O2  2Na2O
(= Na2O + Na2O)
solution: Add the coefficient ‘2’ in front of Na2O
Take atomic inventory again:
Reactants:
Na
O
1
2
Products:
Na
O
4
2
Problem: begin with 1 sodium atom but end with 4.
This breaks the law of conservation of matter.
4 Na + O2  2Na2O
solution: Add the coefficient ‘4’ in front of Na
Take atomic inventory again:
Reactants:
Na
O
4
2
Products:
Na
O
4
2
4 sodium atoms combine with 1 oxygen molecule to
form 2 formula units of sodium oxide. This equation
obeys the Law of Conservation of Matter.
Summary 9

BALANCE THE FOLLOWING REACTION:
H2(g) + O2(g)  H2O(l)
Weird things: polyatomic ions

Ionic compounds can be formed with
polyatomic ions (made from many atoms)
 CO32= one carbon and three oxygen atoms
SO42 OH NH4+
Sometimes you can treat a polyatomic ion
like one atom sometimes you must balance
individual atoms


Summary 10

Identify the polyatomic ions in the
following compounds:
1.
2.
3.
4.
5.
6.
CO2
KNO3
NaOH
CuCl2
Li3PO4
NH4OH
Balancing with polyatomic ions

Sometimes polyatomic ions break apart in a
chemical reaction and sometimes they do not
 e.x. sulfate appears on both sides of the
reaction so SO4 can be treated like one atom:
Mg(s) + CuSO4(aq)  MgSO4(aq) + Cu(s)
 e.x. carbonate breaks apart so atoms must
be balanced individually:
CaCO3(aq) + HCl(aq)  CaCl2(aq) + H2O(l) + CO2(g)
Summary 11

Balance the following equations:
1.
Na2CO3(s) + HCl(aq)  NaCl(aq) + CO2(g) + H2O(l)
2.
K2SO4(aq) + CaCl2(aq)  CaSO4(s) + KCl(l)
Types of Chemical Reactions.
1. Combination.


Also called synthesis
Two or more reactants combine to
form one product
 e.x. 2 Na(s) + Cl2(g)  2 NaCl(s)
 A + B  AB
http://chemed.chem.purdue.edu/demos/main_pages/7.1.html
Summary 12
Which equation represents a synthesis
reaction?

2Ca(s) + O2(g)  2CaO(s)

2KClO3(s)  2KCl(s) + O2(g)
2. Decomposition.

One reactant decomposes to form
two or more products.
 2H2O(l)  2H2(g) + O2(g)
 AB  A + B
Summary 13
Which equation represents a decomposition
reaction?

Ca(s) + O2(g)  CaO(s)

2KClO3(s)  2KCl(s) + O2(g)
3. Single Replacement.

An atom replaces an ion in a compound.

Mg(s) + CuSO4(aq)  MgSO4(aq) + Cu(s)

Cl2(g) + 2KI(aq)  I2(s) + 2KCl(aq)

A + BC  AC + B
Summary 14
Which equation represents a single replacement
reaction?
• 2NaI(s) + Cl2(g)  2NaCl(s) + I2(s)
• 2NaI(aq) + Pb(NO3)2(aq)  2NaNO3(aq) + PbI2(s)
4. Double Replacement.


Ions from different compounds switch
places.
CaCO3(s) + 2HCl(aq)  CaCl2(s) + H2CO3(aq)

AB + CD  AD + CB
Summary 15
Which equation represents a double replacement
reaction?
• 2NaI(s) + Cl2(g)  2NaCl(s) + I2(s)
• 2NaI(aq) + Pb(NO3)2(aq)  2NaNO3(aq) + PbI2(s)
5. Combustion reactions.



A compound reacts with oxygen
often produces CO2 & H2O
e.x. C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g)
Summary 16

Write the balanced equation for the
reaction of CO with O2 to form CO2 and
identify the type of reaction.
Standard 3e:
The Arithmetic of Equations.

A balanced equation shows the
amount of each reactant and product
needed or produced in any reaction.
Example.


Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
One atom of magnesium combines with 2
formula units of HCl to form one formula
unit of magnesium chloride and one
molecule of hydrogen gas.

Use equation coefficients to solve quantitative
problems.
Summary 17
4Na(s) + O2(g)  2Na2O(s)
1.
2.
3.
How many molecules of oxygen are
needed to react with 4 atoms of sodium?
How many oxygen atoms is that?
How many formula units of sodium oxide
are produced when 4 atoms of sodium
are used?
Example.



Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
If 1 atom of magnesium is used, 2 formula
units of HCl are needed to react.
If 6 atoms of magnesium are used, how
many formula units of HCl are needed?
6 atom Mg
2 Fo.U. HCl
1 atom Mg
= 12 Fo.U. HCl
Anatomy of a conversion
T-Chart:
multiply everything on top and
divide by everything on the bottom
Given(units) Units for answer
Units of given
What you
know
Conversion
factor
= answer
What
you
get
Summary 18
Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)

if 4 molecules of H2 are created
1.
2.
how many Fo.U. of HCl are needed?
How many atoms of Mg are used?
Standard 3b: The Mole
Atoms and molecules are so small
scientists must use a large number of
atoms, molecules or formula units in order
to observe chemical reactions. This large
number is called: A Mole
Standard 3c: Avogadro’s Number
The number of particles in one mole =
Avogadro’s number
= 6.02 x 1023
= 602,000,000,000,000,000,000,000
Particles = atoms,
molecules,
formula units,
donuts…
Summary 19

How many dollars would you have if you
had Avogadro’s number of dollars?
How big is a mole?
If every person on earth
(6 billion people)
started counting 1 mole of objects
(6.02 x 1023 objects)
And everyone could count one object per
second it would take…
Over 3 million years
to count to Avogadro’s number!

One mole of dollars would allow you to
give away 1 million dollars to every person
on earth every day for nearly 300,000
years.

One mole of paper would reach outside
our solar system.



If you added 1 mole of ‘special’ water
molecules to the world water supply…
And waited until it was mixed in…
every cup of water on earth would
contain over 100 molecules of ‘special’
water



One mole of atoms fits in the palm of my
hand.
Avogadro’s number is convenient
because a mole of any chemical is easily
measured in the laboratory.
Instead of using 6.02 x 1023 atoms we
use 1 mole of atoms.
Summary 20
4Na(s) + O2(g)  2Na2O(s)
1.
2.
3.
How many moles of O2 are needed to
react with 4 moles of sodium?
How many moles of O2 are needed to
react with 2 moles of sodium?
How many moles of Na2O are produced
when 2 moles of sodium are used?
particles
Moles
Standard 3e:
stoichiometry
coefficients
volume
Moles
1 mole
Molar mass(g)
Molar mass(g)
1 mole
mass

1 Mole of any atom has a
mass (in grams) numerically
equivalent to the mass of a
single atom (in amu). This
mass is displayed on the
periodic table.
Summary 21

What is the mass of one mole of:


Aluminum?
Carbon?
Standard 3d: Molar Mass
= the mass of one mole of any substance.

Example: Na2O
Sodium = 23g/mole
Oxygen = 16g/mole
1 mole Na2O:
(2x23g/mole) + 16g/mole =
The molar mass for Na2O = 62g/mole
Summary 22

calculate the molar mass of AlCl3 (don’t
forget units!)
examples

What is the mass of 3 moles of sodium
hydroxide?
Molar mass!
3 moles NaOH
40 g NaOH
1 mole NaOH

= 120 g NaOH
How many moles of carbon dioxide are in
a sample weighing 88g?
88g CO2
1 mole CO2
44g CO2
= 2 moles CO2
Summary 23
A person produces just less than 0.5 moles
CH4 per day. How many grams is that?
The volume of a Mole
1 mole of any GAS has a
volume of 22.4L at standard
temperature and pressure
 Standard temperature = 0°C
 Standard pressure = 1atm
Summary 24
1. What is the volume of 2 moles of gas?
2. What is the volume of 0.5 moles of gas?
(At standard temperature and pressure)
examples

What is the volume of 3 moles of helium?
3 moles He
22.4 L He
1 mole He

= 67.2 L He
How many moles of nitrogen are inside a
224L container?
224 L
1 mole N2
22.4 L
= 10 mole N2
Summary 25
A person produces just less than 11.2L CH4
per day. How many moles is that
(assume STP conditions)?
particles
Moles
Standard 3e:
stoichiometry
coefficients
volume
Moles
1 mole
Molar mass(g)
Molar mass(g)
1 mole
mass
Example.


Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
If 72g hydrochloric acid are used, how
many liters of hydrogen gas are produced?
73 g HCl 1 mole HCl
36.5 g HCl
1 mole H2
22.4L H2
2 moles HCl 1 mole H2
= 22.4 L H2
Summary 26
1.
2.
Write the balanced equation for the
reaction of hydrogen (H2(g)) with
nitrogen (N2(g)) to form ammonia
(NH3(g)).
If one mole of nitrogen is used:
a.
b.
c.
d.
How
How
How
How
many
many
many
many
moles of hydrogen are needed?
liters (of hydrogen) is that?
moles of NH3(g) are produced?
grams of NH3(g) are produced?
particles
Moles
Standard 3e:
stoichiometry
coefficients
volume
Moles
1 mole
Molar mass(g)
Molar mass(g)
1 mole
mass
examples

How many molecules are contained in 2
moles of CO2?
2 moles CO2
6 x 1023 molecules
= 12 x 1023 molecules
CO2
1 mole CO2
24
= 1.2 x 10

How many atoms are contained in 2
moles of CO2?
2 mol CO2 6 x 1023 molcs 3 atoms
1 mol CO2
1 molc CO2
= 36 x 1023 atoms
= 3.6 x 1024
Summary 27
A person produces just less than 0.5 moles
CH4 per day. How many molecules is
that?
examples

How many molecules are contained in 22g
of CO2?
22g CO2 1 mole CO2 6 x 1023 molecules
44g CO2

1 mole CO2
=
3 x 1023
molecules
What is the mass of 44.8L of CO2?
44.8L CO2 1 mole CO2
22.4L CO2
44g CO2
1 mole CO2
= 88
g CO2
Summary 28
A cow produces about 1500L CH4 per day.
How many grams is that?
Note: Scientific notation




One digit before the decimal ONLY
Number of digits indicates accuracy
Power of 10 indicates magnitude
e.x. 1.0 x 103



Accurate to 2 digits
Number is equivalent to approximately 1,000
e.x 1.0 x 10-3

Number equivalent to 0.0010
Summary 17
Write the following numbers using scientific
notation:
1. 67,000
2. 67,141
3. 0.01
4. 0.0100
Example.


Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
If 2 moles of magnesium reacts, how many
molecules of hydrogen are produced?
2 mole Mg 1 mole H2
1 mole Mg
6.0x1023 molecules H2
1 mol H2
12x1023
=
molecules H2
1.2 x1024 molecules H2
Predicting reactions (Honors only).
Reactions are driven by:

The formation of a solid
e.x. Pb(NO3)2(aq) + 2KI(aq)  PbI2(s) + 2KNO3(aq)

The formation of a gas
e.x. CaCO3(s) + 2HCl(aq)  CaCl2(aq) + H2O(l) + CO2(g)
Solubility Rules (honors only).
All compounds that contain the following
ions are soluble:







group 1
NH4+
NO3HCO3C2H3O2ClO3ClO4-
Solubility Rules (honors only).

All compounds that contain Cl-, Br-, Iare soluble


All compounds that contain SO42- are
soluble


Except: Ag+, Hg+, Pb2+
Except: Ag+, Hg2+, Pb2+ ,Ca2+, Sr2+, Ba2+
All compounds that contain S2- are
insoluble

Except: group 1, group 2, NH4+
Examples (honors only).
ALL OTHER COMPOUNDS ARE SOLIDS
e.x. Pb(NO3)2(aq) + KI(aq)  KNO3 + PbI2


Formation of a solid or gas?
PI2 is solid therefore reaction proceeds
e.x. NaCl(aq) + KNO3(aq)  NaNO3 + KCl
 Formation of a solid or gas?
 No! no reaction