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Review of Grade 9 Chem - Day 1.ppt

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What is Chemistry?

The study of how atoms behave; how they

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Agenda

1. Classifying Matter

2. Physical and Chemical Properties 3. Physical and Chemical Change

4. Atomic Theory and Atomic Numbers 5. Periodic Table Trends

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Classifying Matter By State

Solid

Liquid

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Pure Substances Mixture

Classifying Matter

Matter

Element Compound Mechanical

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Metals and Non-Metals

Metals have these

similar characteristics Silver

Shiny

Good conductors of heat and electricity

Malleable Ductile

Reacts with acid

Non-metals have these similar characteristics

Dull

Brittle

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Physical vs. Chemical

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Physical Properties

Physical properties: are words and/or numbers

that describe matter’s appearance or characteristics

✤ Colour

✤ Melting temperature ✤ Boiling temperature ✤ Texture

✤ Taste ✤ Smell ✤ State

✤ Hardness

✤ Malleability: the ability to be hammered or pressed into a new shape

✤ Ductility: the ability to be deformed without losing toughness; flexible, not brittle

✤ Density: describes how much matter (mass) fits into a certain volume

✤ Conductivity: the ability to conduct thermal energy or electricity ✤ Solubility: the ability to dissolve in another substance

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Chemical Properties

Chemical properties: are words or numbers that describe

how the substance interacts with other substances

✤ Reacts with water ✤ Reacts with air

✤ Reacts with pure oxygen ✤ Reacts with acids

✤ Reacts with other pure substances ✤ Toxicity

✤ Stability

✤ Combustibility: the ability of a substance to burn ✤ Flammability: how easily something catches on

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Practice

For the following properties, identify if they are

physical or chemical

1. A sample of water is 45 ºC

2. Salt dissolves in water

3. Books burn at 455 ºF

4. Copper is a good conductor of electricity

physical

physical

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Qualitative vs

Quantitative

Qualitative: a property that is not measured

and is based on the quality of the substance

 (e.g.) colour, taste, smell

Quantitative: a property that is measured and

has a numerical value

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Practic

e

For the following properties, identify if they

are qualitative or quantitative

1. A sample of water is 45 ºC

2. Baking soda reacts with vinegar

3. Money burns at 455 ºF

Quantitative Qualitative

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Test Your Knowledge

State whether the following properties are

physical or chemical AND qualitative or quantitative

 salt is white in colour

 4 ml of salt dissolves in water

 salt is non-toxic

(a) physical & qualitative

(b) physical & quantitative

(c) chemical & qualitative

(d) chemical & quantitative

(a) physical & qualitative

(b) physical & quantitative

(c) chemical & qualitative

(d) chemical & quantitative

(a) physical & qualitative

(b) physical & quantitative

(c) chemical & qualitative

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Physical and Chemical

Change

Identify the following as a chemical or physical change:

1. Sugar dissolves in tea.

2. Magnesium produces a bright white light when it burns.

3. A nail rusts.

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Chemical Change

Chemical Changes have occurred when a new

substance has formed.

Evidence of a Chemical Change PCGEL

1.Precipitate (a solid is produced) 2.Colour change

3.Gas is produced

4.Endothermic or Exothermic 5.Light is produced

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Physical Change

Physical changes have occurred if there is a

change in appearance or form. In a physical

change, no new matter is formed.

For example:

when you melt ice to make liquid water, no new matter has been formed

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Subatomic Particles

Proton

P

+ Neutron

N

o ELectron

e

Electric

Charge

Positive

neutral

negative

Location

Inside the

nucleus

Inside the

nucleus

Orbiting

the

nucleus

Relative

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n

o

p

+
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Bohr-Rutherford Atomic

Model

How would you draw the Bohr-Rutherford

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Atoms and Numbers

atomic number

number of protons in an atom

number of electrons in a neutral

atom

periodic table is organized by

atomic number

Cl

chlorine 17 36 19 39

Ne

neon 10 20

K

potassium
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Atoms and Numbers

mass number

the sum of the protons and

neutrons

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Atomic Numbers

Copper has:

(a)29 protons, 29 electrons, 29 neutrons (b)29 protons, 29 electrons, 64 neutrons

(c) 29 protons, 29 electrons, 35 neutrons

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Atoms and Numbers

mass number

the sum of the protons and

neutrons

mass # - atomic # = # of

neutrons

Cl

chlorine 17 36 19 39

Ne

neon 10 20

K

potassium

What is the mass number?

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Standard Atomic

Notation

atomic number

mass number

Cu

64

29

mass number

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Cl

chlorine

17

36

Standard Atomic

Notation

Cl

36

17

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Your Turn

Element

Name Element Symbol NumberMass NumberAtomic Number of Protons Number of Neutrons Number of Electrons

Standard Atomic Notation Boron Na Element

Name Element Symbol NumberMass NumberAtomic Number of Protons Number of Neutrons Number of Electrons

Standard Atomic Notation

Boron B 11 5 5 6 5

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Periodic Table

1. Which is the most reactive family of metals on the periodic table?

2. What is the most reactive family of non-metals on the periodic table?

3. What do families on the periodic table have in common?

4. What do periods on the periodic table have in common?

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Periodic Table

The periodic table is an organized way of displaying information about elements.

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Periodic Table

Period

Group 1. Alkali Metals

1

2. Alkaline Earth Metals

2

17. Halogens

17

18. Noble Gases

18 period: a horizontal row

in the periodictable of elements

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Counting Atoms

When determining how many atoms of each

element are in a molecule we look at subscripts

and coefficients

Subscripts are small numbers to the right of an

element symbol. They tell you how many atoms of that particular element there are.

e.g. H2

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Counting Atoms

Subscripts outside of brackets apply to all

elements inside the brackets

e.g. Mg3(PO4)2 = Mg = 3 atoms

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Counting Atoms

Coefficients are regular numbers to the left of

an element or compound. Coefficients affect

ALL of the elements in the compound.

e.g. 2 H2O =H = 4 atoms

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Counting Atoms

How many atoms of each element are in the

following compound: Ni3(PO4)2

(a)N = 6 atoms, P = 1 atom, O = 8 atoms

(b)N = 6 atoms, P = 2 atom, O = 16 atoms

(c)N = 3 atoms, P = 2 atom, O = 8 atoms

(d)N = 6 atoms, P = 4 atom, O = 16 atoms

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The Diatomic Gases

there are 7 elements that exist as diatomic

molecules

hydrogen, oxygen, fluorine, bromine, iodine,

nitrogen, chlorine

HOFBrINCl the clown….

Always written as O2, H2 etc. when the

element is solo in a chemical equation. NEVER just O, H etc.!

He sa ys

References

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