Unit B- Chemistry
Science 9
REVIEW FROM GRADE 8
Learning Concepts
- Explain Workplace Hazardous Materials
Information System (WHMIS) symbols for labeling
substances
- Describe safety precautions for
- Handling substances ...
- Storing substances ...
- Disposing substances ...
... at home and in the laboratory
REVIEW FROM GRADE 8
A hazard symbol has a safety warning and a
shape to indicate how hazardous the material
is
REVIEW FROM GRADE 8
WHMIS stands for Workplace Hazardous
Materials Information System
Designed to help people who use potentially
dangerous materials at work
Lab safety rules:
How can we be safe?
Textbook reference on page 95
Concept 1- Properties
Particle Model of Matter
Matter exists in three states
1. Solid
2. Liquid
3. Gas
- A fourth state is known as plasma – result
when a large amount of energy is added to a
gas
Deposition
Sublimation
-Physical properties of matter can be used for
classification
- When a substance undergoes a physical
change, the appearance/state may be changed
but the composition remains the same
Complete the following table in your notes,
using page 103 as a reference
Practice Questions!! 1-3 in your notes
-Chemical properties of matter describe how a substance interacts
with other substances
- Observable only when a chemical change occurs
- Chemical changes always result in the formation of a different
substance or substances
Includes:
- Reaction with acids
- Ability to burn
-Reaction with water
- Behaviour in air- Reaction to heat
- All matter is either a pure substance or a
mixture
- Both chemical and physical properties tell us
whether a substance is pure or a mixture
-A pure substance is made of only one kind of
matter
- Has a unique set of properties that sets it apart
- May be either an element or a compound
-An element is a material that cannot be broken
down into any simpler substances
- Building blocks for compounds
-When two or more elements combine in a fixed
proportion, a compound is formed
-Mixtures are combinations of pure substances
- Do not combine chemically (in fixed proportions)
- Remain in original, pure form
Four main types of mixtures
1. Mechanical mixture
2. Solution
3. Suspension
4. Colloid
Complete the following table in your notes
using page 103 as a reference
• Recall:
●A
physical change is one where material
changes from one state to another, but its
composition is unchanged
●A
chemical change is one where two or more
materials react and form new materials
•Main
piece of evidence in a chemical reaction is
a change in
● Color
● Odour
(formation of solid or gas)
● Heat released or absorbed (thermal energy)
● State
•Skill
Practice: Identifying Chemical and
Physical Changes
CONCEPT 2 - THEORIES
- Scientific observations refer to different
measurements
- The act of noting or recording something
- An inference or judgement that is acquired
from
observing
- The result of an experiment or trial in which a
variable (qualitative or quantitative) is measured
- Scientific theories are designed to explain
observations
- Must be falsifiable
- Hypotheses are based on theories – theories
may be redefined as new hypotheses are tested
- Can never prove as true ...
- May find supporting data
- May find data that disproves – i.e. Can only prove
as false
False: Spontaneous Generation
-Believed for thousands of years that living things came from non-living
things
-Aristotle: based his ideas on the observation
Maggots seem to generate out of dead animal carcasses Barnacles
forming on the hull of a boat
-Proved wrong by Louis Pasteur
Mould would not appear in an S-shaped container
-John Dalton, an English scientist, used
experimental observations to develop a theory
on the composition of matter
- Put forth the first modern theory of atomic
structure
- Used the term atom
-Basic description of the structure of an element
was correct; other ideas were later modified
-J.J. Thompson contributed to Dalton’s work
- Discovered the electron – a particle smaller
than the atom carrying a negative charge
- Proposed the “raisin bun model”
-Ernest Rutherford used Thompson’s model
while conducting experiments
- Discovered the nucleus – a tiny, positively
charged center in the atom
-Niels Bohr worked with Rutherford
- Suggested electrons did not randomly orbit in
the atom
- Movement was in specific, circular orbits
called electron shells
-Won the Nobel Prize in 1922
-James Chadwick further refined Bohr’s model
- Nucleus contained positively charged particles
called protons and neutral particles called
neutrons
- Neutrons and protons have the same mass,
electrons have 1/1837th the mass
-Patterns and classification bring order to
unorganized ideas
-Matter can be organized in several ways
- Based on state
- Pure substance or mixtures
-The organization of elements was a goal of
early chemists
- Based on observations
-Initially chemists tried to group the elements
based on their properties
- Different scientists organized things in
different ways
- Needed a universal system so everyone used
the same thing
John Dalton developed a set of symbols for
elements
Jons Jacob Berzelius modified this system in
1814
Used capital letters rather than pictures
•Once
a universal system for communicating
elements was in place, there was a need to
organize the elements
-Listed in order of increasing atomic mass
- This is the mass of one atom of an element
- The atom is the smallest part of the element which is
representative of that element
-Developed by Dmitri Mendeleev
- Organized in a manner that reflects the patterns in the
properties of the elements
Discovered properties of elements vary
periodically with increasing atomic mass
•
The current periodic table has about 112
known elements
•
Many new elements are being discovered –
can be unstable
●
Created in labs with special equipment, never
been found in nature
●
- Using the periodic table in your notes, and pages 126- 127 & 132-133, create a study
guide which indicates the following:
- Distinguish between metals, non-metals, and metalloids
- Indicate an example of a period, and a group/family
- Using Mercury as an example (see: page 127 Carbon)
- Atomic number
- Symbol
-Atomic mass
-Name
- Ion charge
- Indicate which groups are the Alkali metals, Alkaline-earth metals,Halogens,
Noble gases
Complete the following table of terms using your glossary
as a reference
•
CONCEPT 3- COMPOUNDS
Learning Concept
•Read
and interpret chemical formulas for
compounds of two elements, and give the
IUPAC (International Union of Pure and
Applied Chemistry) name and common name
of these
-Recall the smallest particle possible is the
atom
- From the Greek term atomos meaning
indivisible
-Recall compounds are formed from two or
more elements which make a new substance
Chemical formulas identify which elements and
how much of these elements are in a compound
•
Naming system (nomenclature) for these
formulas is universal – all scientists use them
•
IUPAC – International Union of Pure and
Applied Chemistry
●
Complete the following activity “Working with
Compounds”
•
Homework: Page 125 #1-5
Learning Concept
•Distinguish
between ionic and molecular
compounds, and describe the properties of
some common examples of each
- Ionic compounds consist of a metal and a non- metal
- Formed from oppositely charged ions
- Properties include
- High melting point
- Good conductivity
- Distinct crystal shape
- Solids at room temperature
When an ionic compound is dissolved in water,
the metal and non-metal form an aqueous
solution of ions
•
An ion is an atom or group of atoms
which has an electrical charge
●◾
Due to loss or gain of electrons
●◾
Ion charges are written with a plus (+) sign or a
minus (-) sign in the upper right of the element
•
Using your periodic table, complete
the following chart of ion charges and notations
●◾
Indicate if there was a loss or gain of
●◾
electrons
Some ions can form when certain elements
combine
•
●
Polyatomic ions are groups of atoms acting as one
•There
are two rules to remember when naming
ionic compounds
The chemical name of the metal, or positive
ion, goes first
●
The name of the non-metal, which comes
second, changes its ending to –ide
●
Exception: when using a negative polyatomic
ion, the name remains unchanged
•
Examples:
NaCl
MgS
CaO
AlCl3
•If
a chemical has more than one ion charge, a
Roman numeral is added into the name
Cu ,Cu
● Copper (I), copper (II)
●
+
2+
Three steps in writing the formula for ionic
compounds
Step 1 – Determine the metal element’s symbol
with the ion charge. Determine the non-metal
element’s symbol with the ion charge
Step 2 – Balance the ion charges. The positive
must balance the negative. This will help you
determine how many atoms of each element
you need to include in the formula
Step 3 – Write the formula by showing how
many atoms of each element are shown in it.
Do NOT include the ion charge. If there are
more than one atoms of the element, include
this number as a subscript (smaller, lower)
•Formative
Assessment – Naming Ionic
Compounds
-When two non-metals combine, a pure
substance called a molecule, or molecular
compound is formed
- Can be solids, liquids or gases at room
temperature
- Tend to be insulators (poor conductors)
- Relatively low melting and boiling points
Writing formulas for molecular compounds is
similar to writing formulas for ionic
compounds
•
Ion charge is not used
●◾
Difficult to predict how non-metals will
●◾
combine
- A common name is different than an IUPAC name
The following three rules are applied
1. The first element in the compound uses the element
name
2. The second element in the compound has the suffix –
ide
3. When there is more than one atom in the formula, a
prefix is used which specifies the number of atoms
•
prefixes
•
Modeling Activity – Candy Compounds
CONCEPT 4- CHEMICAL
REACTIONS
Learning Concept
Observe and describe patterns of chemical
change, by observing heat generated or
absorbed in chemical reactions, and identifying
examples of exothermic and endothermic
reactions
•
- Recall a chemical reaction takes place when
two or more substances combine to form new
substances
- Materials at the start of the reaction are
called reactants
- Materials produced at the end of the reaction
are called products
When heat is released/produced in a chemical
reaction, it is referred to as exothermic
•
Burning wood
● Metabolizing food
●
When heat is absorbed, it is referred to as
endothermic
•
●
Chemical cold pack
Learning Concept
Observe and describe patterns of chemical
change, by identifying factors that affect rates
of reaction
•
- There are four factors that can affect the rate of a chemical
reaction
- Presence of a catalyst
- Concentration of reactants
- Temperature of reactants
- Surface area of reactants
Presence of a catalyst
- Catalysts are substances that help a reaction
proceed faster
- Not used up (consumed) during the reaction
- Particular catalysts are called enzymes – a
type of catalyst found in reactions in living
things
•
Concentration of reactants
Greater concentration means faster
●◾
reaction
There are more atoms of each reactant
●◾
available
•
Temperature of reactants
More heat added, the faster the reaction
●◾
occurs
Added heat causes the atoms to move
faster, increasing the chances they will collide
●◾
•
Surface area of reactants
Greater surface area means there is more area
available for reaction
●
Learning Concept
Describe familiar chemical reactions, and represent these reactions by
using word equations and chemical formulas and by constructing
models of reactants and products
•
Observe and describe evidence of chemical change in reactions
between familiar materials, by:
•
Describing combustion, corrosion and other reactions
involving oxygen
●◾
Observing and inferring evidence of chemical reactions
between familiar household materials
●◾
Three types of reactions occur where oxygen is
reacting
•
Combustion – oxygen reacts with a substance
to form a new substance and give off thermal
energy
●
Fire
A hydrocarbon reacts with oxygen
Products are always carbon dioxide and water
vapour
•
•
•
Science Log
A butane lighter is used to light a candle.
Butane and oxygen react to form carbon
dioxide and water vapour.
•
Write the word equation
●◾
Write the chemical equation
●◾
Corrosion – oxygen in air reacts with a metal
- Rust
Science Log
Mater was left out in Radiator Springs for too
long. Because his body was made out of iron,
oxygen reacted with it and produced iron oxide.
- Write the word equation
- Write the chemical equation
Cellular respiration – food (glucose) reacts
with oxygen to produce energy (ATP) water and
carbon dioxide
Science Log
Green plants containing chlorophyll are one of a very small
group of living things that can create their own food – they
are autotrophs. The process of photosynthesis occurs in
the chloroplasts, and involves the reaction of carbon
dioxide and water to produce glucose and oxygen gas.
Write the word equation
Write the chemical equation
- Law of Conservation of Mass states that the
total mass of the products produced in a
reaction is the same as the total mass of the
reactants
- Matter is not created nor destroyed in
chemical reactions
- Ideally, Experiments must be done in a closed
system – no additional material is allowed to
enter or leave
- An open system is one where additional
material can enter or leave