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Chemistry Unit Notes
Topic 1: Exploring Matter

Know your WHMIS safety symbols
 Particle Theory
1. Matter is made up of very small particles
2. Pure substances have their own kind of particle.
3. Particles attract each other
4. Particles always move
5. If you increase temperature the particles move faster
 Classifying Matter:
Pure Substances: - made up of one kind of particle
- can include: Elements, molecules and compound molecules
Mixtures:
-made up of more than particle
-solutions: look like they have only one kind of particle (homogeneous)
- mechanical mixtures: can see more than one kind of particle (homogeneous)
- suspensions: large particles that settle to the bottom of the container
- colloids: smaller particles than suspensions, colloids in liquids are called
emulsions.
Topic 2: Changes in Matter
 Physical change: a change that doesn’t create a new kind of particle (chemical).
They are often easy to reverse. Ex. Cutting, melting, boiling, dissolving etc.
 Chemical Change: a change that does create a new kind of particle (chemical).
Indicators of chemical change
1. heat is produced or absorbed
2. starting material is used up
3. change in colour
4. A material with new properties is formed
5. Gas bubbles form in a liquid
6. A precipitate (solid) forms from mixing two liquids
7. The change is difficult to reverse
Physical properties: Properties that can be measured without a chemical change.
Ex. Density, Melting point
Chemical properties: Properties that can only be observed by having a chemical
reaction. Ex. Combustibility
Topic 3: What are Elements
 Elements are the groups of pure substances that can’t be broken down further
(without nuclear reactions).
 Elements are made out of atoms. Atoms are the smallest, simplest particles of a pure
substance. Atoms can be rearranged to make compounds and molecules.
 All chemical changes are governed by two Laws.
1. The Law of conservation of Mass: in a chemical change the mass of the reactants
always equals the mass of the products.
2. The Law of Definite composition: compounds are pure substances that contain
two or more elements combined in definite proportions.
So for the equation:
Reactants 
Products
CH4 + O2 
H2O + CO2
16g
36g
64g
44g
***** Note that in the above example reactants are on the left side of the arrow,
products are on the right side of the arrow. The mass of the reactants equals 80g and
the mass of the products equals 80g (Law of conservation of mass). You should also
notice that in CH4 there is one Carbon atom, and four hydrogen atoms (Law of
definite proportions).
Electrolysis Reactions:
 Carried out in a Hoffman’s apparatus (shown to the right), it splits water
compounds into oxygen molecules and hydrogen molecules
Water  Oxygen + Hydrogen
H2O  O2 +H2
 The electrolysis reaction proves that compounds are made of more than one
kind of element.
Dalton’s Atomic Theory:
1. All matter is made up of small particles called atoms
2. Atoms can’t be created or destroyed.
3. Atoms of the same element have the same size and mass, but are different from other
element’s atoms.
4. Compounds are created when atoms of different elements link together (bonding- either ionic
or molecular).
**** Dalton thought atoms were small complete single particles (like little balls)
History of Atomic Models:
Thompson: Plum pudding model.
Electrons and protons are mixed
throughout the atom.
Rutherford’s Planetary model: Electrons
go around the nucleus (made of
neutrons and protons) like little planets
around the sun.
Bohr Model: Electrons have orbits
around the nucleus and have fixed
paths.
Electron Cloud model: Electrons are
found in clouds that surround the
nucleus.
Topic 4: Classifying Elements
 All elements are represented by a capital letter (H for hydrogen) or a capital letter and
a lower case letter (He for helium).
Kind of Elements:
There are a 3 kinds of elements:
I. Metals: are found on the left side of the periodic table, are ductile (can be
stretched into wire), malleable (can be pounded into different shapes).
They are also good conductors of both heat and electricity. Metals are
shiny and are solid (except mercury).
II. Metalloids: are found along the staircase in the periodic table. They are
not ductile, they are brittle, they may conduct electricity, but are poor
conductors of heat. Metalloids can be shiny or dull, they are solid.
III. Non-Metals: are found to the right side of the periodic table. They are not
ductile, are brittle, don’t conduct heat or electricity well. They can be
liquid, solid or gas.
Chemical Families:
There are four main chemical families. They are found in the columns (up and
down) on the periodic table. The four chemical families are:
I. Alkali metals: found in column one (left column). They have an
unpaired electron, so they are very reactive. (electrons like to be
in pairs).
II. Alkali Earth Metals: found in the second column. They are less
reactive than the alkali metals, but are pretty reactive.
III. Halogens: found in the seventh column, they are very reactive
because they have an unpaired electron. They react violently
with Alkali metals.
IV. Noble gases: are in the eighth column (right column). They are
not reactive (they don’t have any unpaired electrons), and are
gases. Noble gases are used in lights (eg. Neon lights).
Topic 5: The Periodic Table
 Mendeleev created the periodic table. He created by comparing the properties of
different known elements.
 The properties uses were reactivity (what reacts with what), density, melting
point, boiling point.
 The columns have similar reactivity.
 Elements are ordered so they are in increasing atomic mass.
 Mendeleev was able to predict undiscovered elements because of his table.
Atomic Mass and Atomic Number:
The modern periodic table is organized by increasing atomic number.
The atomic number = # protons
The atomic mass = # protons + # neutrons
The overall charge of the atom is determined by the number of electrons
compared to the number of protons.
19
F

Flourine Mass number =19  19 heavy particles (protons and neutrons)
Atomic number = 9  9 (protons, which are positively charged)
9
If the fluorine has a charge of 0 (neutral charge) then there are 9 electrons
******If fluorine has a charge of -1, then there are 10 electrons (one more
negative charge than positive charge)
Element Name
Chemical
Atomic
Atomic
# of
#Neutrons #Electrons
Symbol
Number
Mass
Protons
Mercury
Hg
80
200.59
80
121
80
Chlorine
17
35
17
18
Cl18
*** note, when the atom is charged the number of electrons changes, when uncharged the
number of electrons = protons
Topic 6: Chemical Compounds
There are 4 types of compounds you should know:
Type of
Compound
Diatomic
Binary
Description
Example
-Has only got two of the same atom
-Has only two types of elements
Molecular
-Shares electrons between atoms
-Does not contain metals
-Atoms have either positive or negative charges.
-Atoms held together (opposites attract)
-Contains a metal and a non-metal or metalloid
-Conducts electricity pretty well (in solution).
O2, H2, N2
NO, H2O, CO2,
NaCl
NO, H2O, CO2
Ionic
NaCl, MgCl2, Na2O
Naming Chemical Compounds:
Ionic Compounds:
1. Write the metal name
2. Write the name of the non-metal/metalloid, with “ide” at the end.
Ex. NaCl  sodium chloride
MgCl2 magnesium chloride
Molecular Compounds:
1. Write the name of the first element
2. Change the name of the second element to “ide”
3. Use a prefix for the last element [mono (1), di (2), tri (3), tetra (4)] and use a
prefix for the first element *** but don’t if there is only one
[di (2), tri (3), tetra (4)]
Ex. CO2  Carbon Dioxide
Ex. H2O  Dihydrogen monoxide
Ex. H2O2  Dihydrogen dioxide
Topic 7 &8
Energy in Chemical Reactions
i) Energy: 2 categories
Kinetic
Potential
(movement of particles)
(stored energy)
sound
gravitational
electrical (current)
chemical
mechanical
elastic
light
electrical (static)
ii) Exothermic Reactions
 release energy (usually heat)
 e.g.
combustion
Cu(II)SO4 + steel wool  heat + other products
iii) Endothermic Reactions
 absorb energy (usually heat)
 e.g.
baking muffins
Controlling Chemical Reactions
Reaction rates can be controlled with:
iv) Surface Area
 As surface area increases, rate of reaction will increase
 As surface area decreases, rate of reaction will decrease
 (painting, galvanizing etc)
v) Concentration
 As concentration increases, rate of reaction will increase
 As concentration decreases, rate of reaction will decrease
vi) Temperature
 As temperature increases, rate of reaction will increase
 As temperaturedecreases, rate of reaction will decrease
v)
Inhibitors
 Chemicals that slow down reactions
vi)
Catalysts
 Chemicals that Speed up reactions
Corrosion
 chemical reactions that use up metals are corrosion reactions
 metals are 'eaten away' (corroded)
 e.g. rusting of iron
vii) Preventing corrosion
 reduce surface area by painting, covering etc.
 reduce temperature by storing in cold place, in the shade, etc.
 reduce concentration by storing away from high humidity or corrosive
fumes
Law of Conservation of Mass:
In a chemical reaction the mass of the products always equals the mass of the reactants,
because atoms aren’t made or destroyed. They are just rearranged.
Mass of reactants = Mass of Products.
Balancing Chemical Equations:
There is an equal number of each kind of atom in the reactants as there are in the
products.
*****(this comes from the law of conservation of mass, since there is equal mass
or reactants and products, the number of each atom in the reactants and products
must be equal).
1C2H4
C= 2x2 = 4
H= 2x4 = 8
+ 3O2
O= 6x2 = 12

2CO2 +
2H2O
C= 4x1 = 4
O= 4x2 = 8
H= 4x2 = 8
0= 4x1 = 4