Review of Chemistry 20

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. No eating or drinking in the lab.2. Treat all chemicals as if they were hazardous:3. Never perform unauthorized experiments.4. Report all accidents immediately. 5. 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 Base Unit Symbol

length metre m

mass gram g

volume litre L

temperature kelvin K

time second s

amount of matter mole mol

electric current ampere A

SI DERIVED UNITS

Quantity Name of Unit Symbol in SI Base Units

density kilogram per kg · m-3 kg · m-3 cubic metre

(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 1 000 000 000 000 1012

giga G 1 000 000 000 109

mega M 1 000 000 106

kilo k 1 000 103

hecto h 100 102

deca da 10 101

THE BASE UNIT 1 100

SI Prefixes

Prefix Symbol Multiplication Factor Exponential Notation

THE BASE UNIT 1 100

deci d 0.1 10-1

centi c 0.01 10-2

milli m 0.001 10-3

micro μ 0.000 001 10-6

nano n 0.000 000 001 10-9

pico p 0.000 000 000 001 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 s0.000 049 3 N = 4.93 x 10-5 N0.000 000 002 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 i) 1500 ºCb) 0.5306 kg j) 0.0062 Lc) 0.0128 km k) 2.300 kPad) 20 apples l) 8.0 Je) 1.03 x 104 N m) 15 000 000 Af) 406.010 mol n) 120. mmg) 0.00920 g o) 500 studentsh) 90 502 cm p) 100 000 t

SIGNIFICANT DIGITS

a) 18.56 m 4 i) 1500 ºC 2 b) 0.5306 kg 4 j) 0.0062 L 2 c) 0.0128 km 3 k) 2.300 kPa 4 d) 20 apples ∞ l) 8.0 J 2 e) 1.03 x 104 N 3 m) 15 000 000 A 2

f) 406.010 mol 6 n) 120. mm 3g) 0.00920 g 3 o) 500 students ∞h) 90 502 cm 5 p) 100 000 t 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


if the following digit is equal to 5, followed by a nonzero digit, the last digit is increased by 1


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 rounded to 4 s.d. is now 123.4 g123.55 g rounded to 4 s.d. is now 123.6 g

Rounding Off

a) 6.249 mm 2 s.d. b) 10.98 g 3 s.d. c) 0.0573 mol 2 s.d. d) 69.95 km/h 2 s.d. e) 298.036 cm3 4 s.d. f) 349.9 A 3 s.d.g) 9.100 g 2 s.d.h) 56087250 N 4 s.d.i) 21.35 m 3 s.d.j) 450.5 kL 3 s.d.k) 67.77 mg 1 s.d.l) 2880 L 4 s.d.m) 675 J 2 s.d.

Rounding Off

a) 6.249 mm 2 s.d. 6.2 mmb) 10.98 g 3 s.d. 11.0 g c) 0.0573 mol 2 s.d. 0.057 mol d) 69.95 km/h 2 s.d. 70. km/h 7.0 x 101

km/he) 298.036 cm3 4 s.d. 298.0 cm3 f) 349.9 A 3 s.d. 350. A 3.50 x 102 Ag) 9.100 g 2 s.d. 9.1 gh) 56087250 N 4 s.d. 5.609 x 107 Ni) 21.35 m 3 s.d. 21.4 mj) 450.5 kL 3 s.d. 450. kL 4.50 x 102 kLk) 67.77 mg 1 s.d. 70 mgl) 2880 L 4 s.d. 2880. L 2.880 x 103 Lm) 675 J 2 s.d. 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 = 40. 53 m2

= 41 m2

26.2 g ÷ 12.01 g/mol = ? 26.2 g ÷ 12.01 g/mol = 2.18151.. mol

= 2.18 mol

142 mL x ( 1 L / 1000 mL ) = ? 142 mL x ( 1 L / 1000 mL ) = 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 1 t

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 mL5.38 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 1L

1000 mL

= 0.0151 L

Metric Conversion

1) 16 kg = ? g

2) 0.036 s = ? ns

3) 632 cm = ? km

4) 7120 Mg = ? Tg

5) 2.18 x 105 μN = ? mN

6) 8.88 x 10-10 kL = ? mL

Metric Conversion

1) 16 kg = ? g= 16 kg x 1000 g = 1.6 x 104 g

1 kg2) 0.036 s = ? ns

= 0.036 s x 109 ns = 3.6 x 107 ns 1 s

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

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Review of Chemistry 20