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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).

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Review of Chemistry 20

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  1. Review of Chemistry 20 What you really need to remember !

  2. Review Topics • Lab safety (WHMIS, household symbols) • Math (sig figs, scientific notation, dimensional analysis) • Nomenclature (inorganic, organic) • Chemical reactions (types of reactions and balancing)

  3. 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.

  4. 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

  5. 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

  6. Flammable • are substances which can burn easily or cause other materials to burn

  7. 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

  8. 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

  9. WHMIS Workplace Hazardous Materials Information System

  10. Class A - Compressed Gas • danger lies in the pressure, not in the contents.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  19. Metric System

  20. SI BASE UNITS QuantityBase UnitSymbol length metre m mass gram g volume litre L temperature kelvin K time second s amount of matter mole mol electric current ampere A

  21. SI DERIVED UNITS QuantityName 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 )

  22. 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

  23. 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

  24. 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 1023atoms

  25. 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

  26. SCIENTIFIC NOTATION • If the decimal does not have to be moved, the exponent is zero. Example: 1.23 cm = 1.23 x 100 cm

  27. 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.

  28. 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

  29. 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

  30. 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.

  31. 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.

  32. 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.

  33. SIGNIFICANT DIGITS a) 18.56 m i) 1500 ºC b) 0.5306 kg j) 0.0062 L c) 0.0128 km k) 2.300 kPa d) 20 apples l) 8.0 J e) 1.03 x 104 N m) 15 000 000 A f) 406.010 mol n) 120. mm g) 0.00920 g o) 500 students h) 90 502 cm p) 100 000 t

  34. 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 3 g) 0.00920 g 3 o) 500 students ∞ h) 90 502 cm 5 p) 100 000 t 1

  35. 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 rounded to 4 s.d. is now 123.4 g 123.55 g rounded to 4 s.d. is now 123.6 g

  36. 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.

  37. Rounding Off a) 6.249 mm 2 s.d. 6.2 mm b) 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/h e) 298.036 cm3 4 s.d. 298.0 cm3 f) 349.9 A 3 s.d. 350. A 3.50 x 102 A g) 9.100 g 2 s.d. 9.1 g h) 56087250 N 4 s.d. 5.609 x 107 N i) 21.35 m 3 s.d. 21.4 m j) 450.5 kL 3 s.d. 450. kL 4.50 x 102 kL k) 67.77 mg 1 s.d. 70 mg l) 2880 L 4 s.d. 2880. L 2.880 x 103 L m) 675 J 2 s.d. 680 J

  38. 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

  39. 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

  40. 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.

  41. 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

  42. 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

  43. 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 mL 5.38 g/mL

  44. 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

  45. 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

  46. 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

  47. 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) =

  48. 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

  49. 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

  50. 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

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