Transcript Unit 3 Notes

Science 10
Energy and Matter in Chemical Change
Properties of Matter (A1.0)
Classification of Matter (A2.0)
Chemical Reactions (A3.0)
A1.0 Properties of Matter
Lab Safety
Properties of Matter
Theories of Matter
Lab Safety
• Lab safety contract and rules
• Safety hazard symbols identify
dangerous materials in household
products
• WHMIS symbols identify dangerous
materials in the workplace or school
• MSDS are detailed information sheets
about dangerous materials
Properties of Matter
• Matter: anything that takes up space
(solid, liquid, gas or plasma)
• Chemical: any pure substance or
mixture of pure substances
• Physical Property: an observable
characteristic of matter including
colour, texture, hardness, malleability,
ductility, boiling point and melting
point
Properties of Matter
• Chemical Property: a description
of how a substance reacts when
exposed to another substance
• Pure Substance: a substance
that has fixed properties and
cannot easily be separated into
its components
Properties of Matter
• Element: a pure substance made up of
only one type of atom
• Compound: a pure substance made up or
more than one type of element
• Mixture: a combination of two or more
pure substances
• Mechanical Mixture: a mixture in which
the pure substances are distinct
(heterogeneous)
Properties of Matter
• Solution: a mixture in which the pure
substances are not distinct
(homogeneous)
– Solute: the substance dissolved
– Solvent: the substance that
dissolves the solute
• A chemical reaction occurs when a
substance reacts to form new
substances
Properties of Matter
• Evidence of a chemical reaction may
include:
– A change in state, melting point, colour
or density
– A change in temperature
– Formation of a gas (bubbles) or a
precipitate (solid particles in a previously
clear solution)
• Chemical reactions must obey the law of
conservation of mass
Theories of Matter
• Historical use of chemistry has included
1. Food Chemistry
Heating and freezing
Salting
Fermentation
2. Metallurgy
Annealing, ores and alloys
3. Alchemy
Ancient “science”
Theories of Matter
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An atom is the smallest particle of an
element that retains the properties of the
element
Atomic theory has evolved over the years:
Dalton: billiard ball model
Thompson: plum pudding model
Rutherford: nuclear model
Bohr: energy level model
Quantum: electron cloud model
A2.0 Classification of Matter
The Periodic Table and Atomic Structure
Naming Ionic and Molecular Compounds
Properties of Ionic and molecular Compounds
Acids and Bases
Our Chemical Society
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The Periodic Table and
Atomic Structure
All known elements are grouped
according to physical and chemical
properties
Information contained in the Periodic
Table includes:
Element Symbol
Element Name
Period Number
Family Number
The Periodic Table and
Atomic Structure
5. Atomic Number
6. Other information
• Atomic mass
• SATP State
• Metal/Non-metal/Metalloid
• A Bohr model illustrates the relative
locations of the protons, neutrons and
electrons of an atom
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The Periodic Table and
Atomic Structure
A valence electron is an electron that
is in the highest energy level of an
atom
A Lewis diagram depicts the valence
electrons in an atom
The Rule of Octets states that atoms
bond in such a way as to have a full
valence level
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Naming Ionic and
Molecular Compounds
Ionic compounds are formed when a
metal donates one or more electrons to a
non-metal
The metal becomes a positively charged
ion (cation) while the non-metal becomes
a negatively charged ion (anion)
Positive ions attract negative ions to form
a stable crystal lattice
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Naming Ionic and
Molecular Compounds
Naming binary ionic compounds:
1. Name the cation first by using the
element’s name
2. Name the anion second by using
the first part of the element name
and changing the ending to “ide”
3. Include the state of matter
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Naming Ionic and
Molecular Compounds
Writing formulas of binary ionic
compounds:
1. Identify the anion and cation
2. Determine the total charges needed
to balance
3. Note the ratio of cations to anions
4. Use subscripts to write the formula
Naming Ionic and
Molecular Compounds
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Naming multivalent ionic compounds:
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Identify the anion
Use the charge of the anion to determine which
version of the cation to use
Write the name of the cation with a roman
numeral to indicate which version is used
Write the name of the anion and change the
ending to “ide”
Include the state of matter
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Naming Ionic and
Molecular Compounds
Writing the formulas of multivalent
ionic compounds:
1. Identify the anion and cation
2. Determine which version of the
cation is used
3. Determine the total charges needed
to balance
4. Note the ratio of cations to anions
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Naming Ionic and
Molecular Compounds
Naming polyatomic ionic
compounds:
1. Identify the cation and write the
element name
2. Identify the polyatomic anion and
write its name
3. If necessary use a roman numeral
to indicate which version of the
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Naming Ionic and
Molecular Compounds
Writing the formulas of polyatomic
ionic compounds:
1. Identify the cation and polyatomic
anion
2. Determine the total charges needed
to balance
3. Note the ratio of cations to anions
4. Place brackets around the anion if
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Naming Ionic and
Molecular Compounds
Molecular compounds are formed
when two non-metals share a pair of
valence electrons
A covalent bond is a shared pair of
electrons
The number of shared pairs of
electrons determines the number of
covalent bonds between two atoms
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Naming Ionic and
Molecular Compounds
Molecular elements contain atoms of only one
element
Molecular elements can be monatomic, diatomic and
polyatomic
Binary molecular compounds that do not contain
hydrogen can be named:
1. Use a prefix to indicate the number of the first
element
2. Use a prefix to indicate the number of the
second element and change the ending to “ide”
3. Include the state of matter
Naming Ionic and
Molecular Compounds
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To write the formulas of binary molecular
compounds:
1. Use the prefix of the first element to
determine the number of that element
2. Use the prefix of the second element to
determine the number of that element
• Molecular compounds that contain
hydrogen have unique names that must be
memorized
Properties of Ionic and
Molecular Compounds
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Ionic compounds:
1. Have a high melting point (solid at
SATP)
2. Retain a crystal shape
3. Dissolve in water
4. Conduct electricity when dissolved
The solubility of ionic compounds can be
predicted using a solubility table
Properties of Ionic and
Molecular Compounds
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Molecular compounds:
1. Have low melting points (can be solid,
liquid or gas at SATP)
2. Do not conduct electricity when dissolved
Water is a molecular compound with special
properties including:
High boiling point
Low density as a solid
High polarity
Acids and Bases
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Acids:
1. Are aqueous compounds with that
dissolve to form hydrogen ions
2. Have a pH level less than 7
3. React with metals to make hydrogen
gas
4. Taste sour
5. Can be neutralized with bases
Acids and Bases
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Bases:
1. Are aqueous compounds with that
dissolve to form hydroxide ions
2. Have a pH level greater than 7
3. Taste bitter
4. Feel slippery
5. Can be neutralized with acids
Acids and Bases
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An indicator is a chemical that
changes colour depending on the pH
of the solution to which it is added
Litmus paper is an indicator
A universal indicator is a mixture of
indicators that can determine the
precise pH of a solution
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The use of industrial and household
chemicals has risks
Environmental (example: CFC’s)
Health (Examples: alcohol, nicotine,
benzene)
Several careers relate to chemistry
Food Technologist
Cosmetics Formulator
Petroleum Engineer
Chemical Reactions
Examples of Chemical Change
Writing Chemical Equations
Types of Chemical Reactions
The mole
Examples of Chemical Change
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Different examples of chemical changes
include
Reactions that form gases
Reactions that form solids
Exothermic reactions
Endothermic reactions
Biochemical reactions including
photosynthesis and cellular respiration
Examples of Chemical Change
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Characteristics of chemical reactions
include:
The production of new substances
with new properties
The flow of energy
A change of state
The observance of the law of
conservation of mass
Writing Chemical Reactions
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A word equation is a sentence that
accurately describes a chemical
change
A balanced chemical formula
equation uses appropriate symbols
to accurately describe a chemical
change
Types of Chemical Reactions
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There are five types of chemicals reactions
we will study
1. Formation
(element + element  compound)
2. Decomposition
(compound  element + element)
3. Hydrocarbon Combustion
(hydrocarbon + oxygen gas 
carbon dioxide gas + liquid water)
Types of Chemical Reactions
4. Single Replacement
(element + compound element + compound)
5. Double Replacement
(compound + compound  compound + compound)
The Mole
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A mole is a quantity use in chemistry to
measure elements and compounds
One mole equals 602 000 000 000 000 000
000 000 particles
Avogadro’s Number = 6.02 x 1023
Molar mass is the mass of one mole of a
substance
Number of moles = mass / molar mass