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Chemistry 9 - Review
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1. Classification Of Matter
Oxygen
Water
Salt
Water &
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Name the following
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H2
O2
N2
NH3
CH4
H2O
CO2
NaCl
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Hydrogen
Oxygen
Nitrogen
Ammonia
Methane
Water
Carbon Dioxide
Sodium chloride
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2. Properties
a) Physical
A) Qualitative:
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State :solid, liquid, gas.
Color: colorless, black, white …
Texture: rough, smooth or bumpy
Form : crystals, cubes, powder,
hexagon, wire, sheet
Odour: strong, weak, sweet,
mouldy, odourless.
Lustre : shinny or dull
Clarity : transparent, translucent,
opaque
Malleability : soft, pliable, hard can bend (e.g. Al)
Ductility : ductile – can stretch
(Cu)
B) Quantitative
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Melting Point: high or low
(ice → water @ 0˚ C)
Boiling Point : high or low
(water → water vapour @100˚ C )
Density = Every substance has a unique
density (g/ml)
Solubility : soluble or insoluble. Capacity
to dissolve in another substance
Viscosity: high or low. The measure of a
substance’s resistance to flow. (e.g.
maple syrup has a high viscosity)
Hardness: hard or soft. Ability to scartich
another material (e.g. : icing sugar vs.
table salt)
Conductivity: high or low. Ability to
conduct electricity or heat.
b) Chemical
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The ability of a substance to react
with another - behaviour
a) Combustibility
b) Reaction
with acid
c) Reaction with water
d) Toxicity
e) Stability
Describe these substances
Copper (Cu)
Aluminum (Al)
Table (NaCl)
Icing Sugar
3. The Particle Theory of Matter.
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All matter is made up of tiny particles.
Particles can’t be created nor destroyed.
All particles of the same elements are
identical.
Particles attract each other.
Particles are always moving.
Particles at a higher temperature move
faster.
4) How is density determined?
• Density is mass divided by volume, or D = m/v.
• Common units are g/cm3 or g/mL
• Water has a density of 1 g/mL. Thus, objects with
density greater than 1 g/mL will sink in water.
Objects with density less than 1 g/mL float in water.
• M=v•d
• V= m/d
Example
A sample of aluminum metal has a mass of 8.4 g.
The volume is 3.1 cm3. Find the density.
Known
Unknown
m = 8.4 g
D=?
V = 3.1 cm3
5) Gas Tests
Test
1. Place a burning splint in the
presence of the unknown gas
Result
If you hear a « pop »,
and the splint goes
out, it’s Hydrogen.(H2)
If the splint goes out,
it’s Carbon dioxide
(CO2)
2. Place a glowing wooden splint If the glowing splint
in the presence of the
ignites (relights), it’s
unknown gas.
Oxygen (O2)
Hydrogen Gas Test
Carbon Dioxide Gas Test
With lime water
Burning splint
Oxygen Gas Test
6) Modern Periodic Table
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The horizontal rows are
called periods
The vertical columns
are called groups are
labeled from 1 to 18.
Elements in the same
group have similar
chemical and physical
properties!!
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7) How are elements organised today?
Elements are organised according to their
atomic number.
•Elements are classified in three groups:
1. Metals(to the left of the stairs)
2. Non-metals(to the right of the stairs)
3. Metalloids (around the stairs)
Must round to 11
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Neutrons = 11-5
Boron has 6
neutrons.
8) Standard Atomic Notation
9) Bohr-Rutherford Atomic
model
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# e-= p+= atomic #
# n = atomic Mass –
atomic #
Stable atom = last orbit
is complete (saturated).
Ion = an atom where # p+
≠ # e+ ion = an atom that has
lost e-. (Mg+2)
- ion = an atom that has
gained e-. (N-3)
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10)Valence electrons = # of
electrons on the last orbit
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Each group has the
same # of valence e(electrons on the last
orbit)
Practice
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11) Types de compounds:
1) Ionic Compounds:
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Its a molecule made of a metal and one
or more non-metals.
In this type of compounds, there is a
transfer of e-→ The metal loses e- and
the non-metals gains e- to form an
ionic bond.
Physical Properties
• They are all crystals – salt.
• They are hard
• They are all soluble in
water.
• When dissolved, they are
are good conductors
“electrolytes”.
• High melting point– it takes
800°C to melt table salt.
• High boiling point.
Covalent Compounds
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It’s a molecule that contains 2 or more
non-metals.
The two atoms share electrons to make
a covalent bond.
E.g. H2O, CO2, CH4
All diatomic molecules (7 non-metals)
are covalent : H2 O2 Br2 F2 I2 N2 Cl2
Physical Properties:
• They can be solid, liquid or gas
• If solid, they are soft.
• Some are soluble in water.
• They are uncharged, so they don’t
conduct electricity.
• Low melting point ( they melt fast,
since they have weak bonds)
• Low boiling point.
Ionic
Covalent
12) How to count atoms?
1 CO2
1 carbon atom
2 oxygen atoms
Total 3 atoms
1 molecule of CO2
2 NaCl
3 MgClO3
2 H2SO4
2 CaCl2
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