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Review of Chemistry 20
What you really need to remember !
Review Topics
 Lab safety (WHMIS, household symbols)
 Math (sig figs, scientific notation, dimensional
analysis)
 Nomenclature (inorganic, organic)
 Chemical reactions (types of reactions and
balancing)
Hazardous Materials in the Home
 The eight-sided outline
(octagonal) signifies that
the contents of the container
is dangerous.
 The triangular outline
signifies that the container
is dangerous, usually because
the contents are under high pressure.
Hazardous Materials in the Home
Poison
 poisons can enter the body in one of three
ways:
a) ingestion (eating)
b) inhalation (breathing)
c) absorption through the skin
d) injection
Corrosive
 are chemicals which can act on clothing, skin,
eyes or internally by drinking or eating
 can cause symptoms ranging from mild rash
to serious skin damage
 can damage clothing
 can cause blindness
 can cause death if ingested
Flammable
 are substances which can burn easily or
cause other materials to burn
Radiation
 radioactive materials emit high energy atomic
particles or high energy radiation (x-rays,
gamma rays), or both
 found in smoke detectors and involve no
danger if kept at a safe distance
Explosive
 can cause injury or death
as a result a blast or because
of the materials expelled by the blast (metal
shards)
 usually are pressurized aerosol containers
which may explode when heated
WHMIS
Workplace
Hazardous Materials
Information
System
 Class A - Compressed Gas
 danger lies in the pressure, not in the contents.
 Class B - Combustible and
Flammable Material
 may burn at relatively low temperatures, burn spontaneously or
as a result of heat, sparks or friction
 hydrocarbons and several chemicals like phosphorus, sodium
and calcium carbide would be included in the list.
 Class C - Oxidizing Material
 may cause a fire, react violently or explode when it comes into
contact with combustible materials such as wood.
 an oxidizer supplies the oxygen for a chemical reaction.
 Class D, Division 1 –
Poisonous and Infectious Material;
Immediate and Serious Toxic
Effects
 these substances have acute toxicity - refers to a substance
which has immediate effects, usually within 24 hours
 Class D, Division 2 –
Poisonous and
Infectious
Material; Other Toxic Effects
 these substances have chronic toxicity - refers to the effects of
a substance through repeated exposure at low levels over a
long period (weeks, months or years).
 effects may be similar to those of acute
toxicity; organ damage, illness or death
 the effects can also include cancer,
allergies or chronic diseases (bronchitis, emphysema, cirrhosis
of the liver, etc.)
 long term alcohol or cigarette use would fall under this category
 Class D, Division 3 –
Poisonous and Infectious Material;
Biohazardous Infectious Material
 refers to an infectious agent
(bacteria, virus or some other
organism) which may spread disease if improperly
handled, also called a biohazard
 this symbol is common in hospital emergency rooms
on containers where used needles and dressings are
deposited
 Class E - Corrosive Material
 causes severe eye and skin irritation upon contact
 causes severe tissue damage with prolonged exposure
 may be harmful if inhaled
 the effects are the same as under the household hazards
 Class F - Dangerously Reactive Material
 is very unstable
 may react with water to release
a toxic or flammable gas
 may explode as a result of shock,
friction or increase in temperature
 undergoes vigorous polymerization
 all of these reactions happen very quickly; you have to be
extremely careful around these substances
Lab Procedures and Rules
1.
2.
3.
4.
5.
No eating or drinking in the lab.
Treat all chemicals as if they were hazardous:
Never perform unauthorized experiments.
Report all accidents immediately.
If you get a chemical solution in your eye go to the eyewash station
immediately and wash the eye for at least 5 minutes.
6. If you get chemicals on your clothes, wash the clothes thoroughly.
7. Do not wear loose clothing during a lab. Tie long hair back.
8. Do not sit on the lab bench; you do not know how clean it is.
9. Clean all equipment thoroughly and put it back where it belongs.
10. Follow directions concerning the safe disposal of chemicals and
solutions.
11. Clean your lab station thoroughly after a lab.
Metric System
SI BASE UNITS
Quantity
length
mass
volume
temperature
time
amount of matter
electric current
Base Unit
metre
gram
litre
kelvin
second
mole
ampere
Symbol
m
g
L
K
s
mol
A
SI DERIVED UNITS
Quantity
Name of Unit
Symbol
in SI Base
Units
density
kilogram per
cubic metre
kg · m-3
kg · m-3
(kg/m3)
force
Newton
N
kg · m · s-2
(kg · m / s2)
pressure
Pascal
Pa
N · m-2
(kg·s-2·m-1 , N / m2)
heat energy
Joule
J
N·m
(kg·m2·s-2 )
SI Prefixes
Prefix
Symbol Multiplication Factor Exponential
Notation
tera
T
giga
G
mega
M
kilo
k
hecto
h
deca
da
THE BASE UNIT
1 000 000 000 000
1 000 000 000
1 000 000
1 000
100
10
1
1012
109
106
103
102
101
100
SI Prefixes
Prefix
Symbol Multiplication Factor Exponential
Notation
THE BASE UNIT
deci
d
centi
c
milli
m
micro
μ
nano
n
pico
p
1
0.1
0.01
0.001
0.000 001
0.000 000 001
0.000 000 000 001
100
10-1
10-2
10-3
10-6
10-9
10-12
SCIENTIFIC NOTATION
For numbers larger than 1
 The exponent is positive
Examples:
3000 m = 3000.0 m = 3 x 103 m
454 000 g = 454 000.0 g = 4.54 x 105 g
3 860 000 L = 3 860 000.0 L = 3.86 x 106 L
602 000 000 000 000 000 000 000 atoms
= 6.02 x 1023 atoms
SCIENTIFIC NOTATION
For numbers smaller than 1
 The exponent is negative
Examples:
0.068 s = 6.8 x 10-2 s
0.000 049 3 N = 4.93 x 10-5 N
0.000 000 002 41 A = 2.41 x 10-9 A
SCIENTIFIC NOTATION
 If the decimal does not have to be moved, the
exponent is zero.
Example:
1.23 cm = 1.23 x 100 cm
SCIENTIFIC NOTATION
 IF A NUMBER IS LARGER THAN 9999 OR
SMALLER THAN 0.001 IT MUST BE
WRITTEN IN SCIENTIFIC NOTATION.
 Between these extremes you may use
either decimal or scientific notation.
SCIENTIFIC NOTATION
 Only 1 non-zero number to the left of the
decimal place:

2630 g
=
≠
≠
≠
2.63 x 103 g
26.3 x 102 g
263 x 101 g
0.263 x 104 g
UNITS
 All numbers are measurements; they have a
numeral and a unit.
 NEVER write a number without a unit behind
it.
12.01 g/mol , not 12.01
SIGNIFICANT DIGITS
1. All non-zero numbers are considered significant; that is, they
are counted:
123 g has 3 significant digits; 1267 m has 4 s.d.
2. There are two situations where zeros are significant:
i)
Zeros between two non-zero numbers
102 L has 3 s.d.; 10203 L has 5 s.d.; 1002 L has 4 s.d.
ii)
A zero at the end of a decimal number
12.00 m has 4 s.d.; 0.010 m has 2 s.d.;
1200.000 m has 7 s.d.
SIGNIFICANT DIGITS
3.
In any other situation zeros are not considered significant:
i) For a number larger than 1, a zero between the decimal
and the first non-zero number
120 s has 2 s.d.; 10200 s has 3 s.d.;
130 000 000 s has 2 s.d.
ii). For a number smaller than 1, a zero between the decimal
and the first non-zero number
0.0012 A has 2 s.d.; 0.02102 A has 4 s.d.;
0.000 000 001 A has 1 s.d.
SIGNIFICANT DIGITS
 Exact numbers


defined (conversion factors in the metric
system)
result from counting objects (like the
coefficients used to balance chemical
equations).
 have an infinite (∞) number of significant
digits for rounding purposes.
SIGNIFICANT DIGITS
a) 18.56 m
b) 0.5306 kg
c) 0.0128 km
d) 20 apples
e) 1.03 x 104 N
f) 406.010 mol
g) 0.00920 g
h) 90 502 cm
i) 1500 ºC
j) 0.0062 L
k) 2.300 kPa
l) 8.0 J
m) 15 000 000 A
n) 120. mm
o) 500 students
p) 100 000 t
SIGNIFICANT DIGITS
a)
b)
c)
d)
e)
f)
g)
h)
18.56 m
0.5306 kg
0.0128 km
20 apples
1.03 x 104 N
406.010 mol
0.00920 g
90 502 cm
4
4
3
∞
3
6
3
5
i) 1500 ºC
j) 0.0062 L
k) 2.300 kPa
l) 8.0 J
m) 15 000 000 A
n) 120. mm
o) 500 students
p) 100 000 t
2
2
4
2
2
3
∞
1
Rounding Off

if the following digit is greater than 5, the last digit is increased by 1
e.g.

123.46 g
rounded to 4 s.d. is now
123.5 g
if the following digit is less than 5, the last digit stays the same
e.g.
123.44 g
rounded to 4 s.d. is now
123.4 g

if the following digit is equal to 5, followed by a nonzero digit, the last digit is
increased by 1
e.g.
123.452 g
rounded to 4 s.d. is now 123.5 g

if the following digit is equal to 5, and not followed by a nonzero digit , the last
digit is increased by 1 only if it produces an even number
e.g.
123.45 g
123.55 g
rounded to 4 s.d. is now
rounded to 4 s.d. is now
123.4 g
123.6 g
Rounding Off
a) 6.249 mm
b) 10.98 g
c) 0.0573 mol
d) 69.95 km/h
e) 298.036 cm3
f) 349.9 A
g) 9.100 g
h) 56087250 N
i) 21.35 m
j) 450.5 kL
k) 67.77 mg
l) 2880 L
m) 675 J
2 s.d.
3 s.d.
2 s.d.
2 s.d.
4 s.d.
3 s.d.
2 s.d.
4 s.d.
3 s.d.
3 s.d.
1 s.d.
4 s.d.
2 s.d.
Rounding Off
a) 6.249 mm
b) 10.98 g
c) 0.0573 mol
d) 69.95 km/h
e) 298.036 cm3
f) 349.9 A
g) 9.100 g
h) 56087250 N
i) 21.35 m
j) 450.5 kL
k) 67.77 mg
l) 2880 L
m) 675 J
2 s.d.
3 s.d.
2 s.d.
2 s.d.
4 s.d.
3 s.d.
2 s.d.
4 s.d.
3 s.d.
3 s.d.
1 s.d.
4 s.d.
2 s.d.
6.2 mm
11.0 g
0.057 mol
70. km/h 7.0 x 101 km/h
298.0 cm3
350. A
3.50 x 102 A
9.1 g
5.609 x 107 N
21.4 m
450. kL 4.50 x 102 kL
70 mg
2880. L 2.880 x 103 L
680 J
Operations With Significant Digits
 Rule for addition and subtraction
 Add or subtract and then round-off so that the answer
is no more precise than the least precise number in
the calculation.
 The units must be the same.




6.1 mL + 2.34 mL = ?
6.1 mL + 2.34 mL = 8.4 mL
91 g + 14.68 g = ?
91 g + 14.68 g = 106 g






22.3 L - 8 L = ?
22.3 L - 8 L = 14 L
4.5 m - 4.4 m = ?
4.5 m - 4.4 m = 0.1 m
36.3 A - 0.0255 A = ?
36.3 A - 0.0255 A = 36.3 A
Operations With Significant Digits
 Rule for multiplication and division



Multiply or divide and then round-off so that
the answer has no more significant digits
than the number with the fewest significant
digits in the calculation.
Remember that any exact numbers do not
enter into the determination of least significant
digits.
Whatever operation is done with the numerals
must also be done with the units.






19.3 m x 2.1 m
19.3 m x 2.1 m
=
=
=
26.2 g ÷ 12.01 g/mol
26.2 g ÷ 12.01 g/mol
?
40. 53 m2
41 m2
=
=
=
142 mL x ( 1 L / 1000 mL ) =
142 mL x ( 1 L / 1000 mL ) =
?
2.18151.. mol
2.18 mol
?
0.142 L
a) 9.54 g + 6.578 g + 10.02 g
= 26 138 g = 26.14 g
b) 8.55 mL + 11.6 mL + 20.0 mL
= 40.15 mL = 40.2 mL
c) 480 km + 24.07 km
= 504.07 km = 5.0 x 102 km
d) 136 g - 3.49 g
= 132.51 g = 133 g
e) 16.56 mL - 6.3 mL
= 10.26 mL = 10.3 mL
f) 51.08 mol - 9.9 mol
= 41.18 mol = 41.2 mol
g) 18.4 g/mL x 5.5 mL = 101.2 g = 1.0 x 102 g
h) 21.4 g x
1 kg
= 0.0214 kg
1000 g
i) 1.0058 t x 1000 kg = 1005.8 kg
1t
j)
6.0 g
= 0.2469 mol = 0.25 mol
24.3 g/mol
k) 358.6 g = 177.52 g/mol = 178 g/mol
2.02 mol
l)
2.64 g
= 0.4907 mL = 0.491 mL
5.38 g/mL
Scientific Notation
 Adding and Subtracting


can only be done if the exponents are the
same.
normal rules for significant digits applies to the
integers.

2.15 x 10-2 g + 4.11 x 10-3 g
= 2.15 x 10-2 g + 0.411 x 10-2 g
= 2.56 x 10-2 g
Scientific Notation
 Multiplying




multiply integers
add exponents
adjust final answer
(5.4 x 102 mol) x (4.000 x 101 g/mol)
=
21.6 x 103 g
=
2.2 x 104 g
Scientific Notation
 Dividing




divide integers
subtract exponents
adjust final answer
(1.4 x 10-2 mol) ÷ (3.62 x 101 L)
=
0.38674... x 10-3 mol/L
=
3.9 x 10-4 mol/L
a) 9.25 m + 4.10 m - 2.05 m =
b) 134.8 g + 2.05 g - 13 g =
c) 14.896 mL - 2.42 mL + 4.60 mL =
d) (3.45 x 10-1 s) - (4.789 x 10-3 s) =
e) (7.95 x 10-2 A) + (2.05 x 10-1 A) =
f) 4.18 L x 0.051 960 mol/L =
g) 0.50 mol ÷ 4.12 L =
h) (9.330 x 10-2 N) x (4.612 x 101 s) =
i) (1.981 x 101 g) ÷ (2.5 x 102 g/mol) =
j) ((4.68 x 10-4 ) x (8.743 x 105)) ÷ (1.04 x 10-2) =
a) 9.25 m + 4.10 m - 2.05 m = 11.30 m
b) 134.8 g + 2.05 g - 13 g = 124 g
c) 14.896 mL - 2.42 mL + 4.60 mL = 17.08 mL
d) (3.45 x 10-1 s) - (4.789 x 10-3 s) =
(3.45 x 10-1 s) - (0.04789 x 10-3 s)
= 3.40 x 10-1 s
e) (7.95 x 10-2 A) + (2.05 x 10-1 A) =
(0.795 x 10-1 A) + (2.05 x 10-1 A)
= 2.84 x 10-1 A
f) 4.18 L x 0.051 960 mol/L = 0.217 mol
g)0.50 mol ÷ 4.12 L = 0.12 mol/L
h)(9.330 x 10-2 N) x (4.612 x 101 s) =
4.303 x 100 Ns
i) (1.981 x 101 g) ÷ (2.5 x 102 g/mol) =
7.9 x 10-2 mol
j) ((4.68 x 10-4 ) x (8.743 x 105)) ÷ (1.04 x 10-2)
= 3.93 x 104
Metric Conversion
 must show the calculation using dimensional
analysis.
 significant digits do not change

151 mL = ? L
= 151 mL x
= 0.0151 L
1L
1000 mL
Metric Conversion
1)
2)
3)
4)
5)
6)
16 kg = ? g
0.036 s = ? ns
632 cm = ? km
7120 Mg = ? Tg
2.18 x 105 μN = ? mN
8.88 x 10-10 kL = ? mL
Metric Conversion
1) 16 kg = ? g
= 16 kg x 1000 g = 1.6 x 104 g
1 kg
2) 0.036 s = ? ns
= 0.036 s x 109 ns = 3.6 x 107 ns
1s
3) 632 cm = ? km
= 632 cm x 1 km = 6.32 x 10-3 km
105 cm
Metric Conversion
4)7120 Mg = ? Tg
= 7120 Mg x 1 Tg = 7.12 x 10-3 Tg
106 Mg
5)2.18 x 105 μN = ? mN
= 2.18 x 105 µN x 1 mN = 2.18 x 102 mN
103 µN
6)8.88 x 10-10 kL = ? mL
= 8.88 x 10-10 kL x 106 mL = 8.88 x 10-4 mL
1 kL