2. 1. Chemical reaction = process by which one or more substances are changed into one or more different substances (atoms are rearranged)

3. a) reactants = original substances(written to the left of the arrow in a chemical equation) b) products = resulting substances(written to the right of the arrow in a chemical equation)

4. Yields Reactants CH 4 + 2O 2 Products CO 2 + 2H 2 O

5. c) Indications of a chemical reaction (chemical change): – evolution of heat and/or light – production of a gas (often seen as bubbles) – color change – formation of a precipitate when two solutions are mixed (Precipitate = a solid that separates from a solution)

6. d) catalyst = a substance that speeds up a chemical reaction but is not permanently consumes in the reaction. –Catalysts DO NOT appear as reactants or products! –Ex: manganese dioxide is a catalyst in the following reaction: 2H 2 O 2 O 2 + 2H 2 O MnO 2

7. 1. Chemical equation = a representation of the reactants and products in a chemical reaction

8. a) Word equation = a chemical equation in which the reactants and products in a chemical reaction are represented by words Ex: sodium + water → sodium hydroxide + hydrogen reactantsproducts

9. b) Formula equation = a chemical equation in which the reactants and products in a chemical reaction are represented by chemical symbols or chemical formulas Ex: Na+ H2OH2O → NaOH+ H2H2 reactantsproducts

10. c) Atom inventory (for a chemical equation) = a “bookkeeping” technique designed to count the number of each type of atom (ion) represented on each side of a chemical equation

11. d) Subscript = whole number that appears to the right and below a chemical symbol in a chemical formula (if no number is written it is assumed to be “1”) – Indicates the number of atoms or ions – Ex: H2OH2O subscriptsubscript (assumed to be “1”)

12. Coefficient = whole number that appears in front of a reactant or product in a balanced chemical equation (if no number is written it is assumed to be “1 1”) ) – Indicates the number of molecules or moles

13. Ex: 2 CO 2 coefficient Al 2 S 3 coefficient (assumed to be “1”)

14. f) Balanced chemical equation = a formula equation where coefficients are added so equal numbers of each type of atom (ion) are represented on each side of the equation Ex: + → 2 NaOH(aq)+2 Na (s) 2 H 2 O (l)H 2 (g) reactantsproducts

15. 2 Na (s)+ 2 H 2 O (l) → 2 NaOH(aq)+ H 2 (g) 2 molecules of solid sodium reacts with 2 molecules of water to yield 2 molecules of aqueous sodium hydroxide and 1 molecule of hydrogen gas. OR 2 moles of solid sodium reacts with 2 moles of water to yield 2 moles of aqueous sodium hydroxide and 1 mole of hydrogen gas.

16. 4 Fe + 3 O 2 → 2 Fe 2 O 3 4 Fe + 3 O 2 What are the reactant(s)?= ___________________________ What are the product(s)? _____________________________ 2 Fe 2 O 3

17. # of moles of O 2 =______________ # of molecules of O 2 =_____________ # of atoms of Fe in 2Fe 2 O 3 = ________ 4 # of atoms of O in 3 O 2 =_________ 3 3 6

18. Symbol Meaning  “yields”;indicates result of a reaction  Indicates a reversible reaction (s)A reactant or product in the Solid state

19. ↓ Alternative to (s);used only for a Precipitate (solid) falling out of solution (l)(l) A reactant or product in the liquid statet (aq)A reactant or product in aqueous Solution (dissolved in water) (g)A reactant or product in the Gaseous state

20. ↑ Alternative to (g);used only for a Gaseous product Δ Reactants are heated 2atmPressure at which the reaction is Carried out, in this case 2 atm

21. OCOC Temperature at which reaction is Carried out, in this case O  C MnO 2 A catalyst is used to speed up the Reaction rate, in this case MnO 2 Would be used to speed up the Reaction rate.

22. 1. The equation must represent the known facts with all reactants and products identified. 2. The equation must contain the correct formulas of the reactants and products.

23. A chemical reaction obeys the “Law of Conservation of Matter” The Law of Conservation of Matter = matter cannot be either created or destroyed in ordinary chemical or physical means.

24. The Law of Conservation of Matter must not be violated! – This means you must balance equations. (Equations are balanced by adding coefficients, NOT subscripts.)

25. 4. Why do we balance equations? –The Law of Conservation of Matter must not be violated!

26. 5. Atomic theory can be used to explain why chemical reactions obey the “Law of Conservation of Matter”. – All atoms present at the start of a chemical reaction are present at the end of that chemical reaction (atoms are simply rearranged during a chemical reaction).

27. –Since no atoms are created or destroyed in a chemical reaction no matter is created or destroyed in a chemical reaction. –Since no matter is created or destroyed in the chemical reaction the mass of the reactants must equal the mass of the products in a chemical reaction.

28. 6. A balanced chemical equation details how a chemical reaction obeys the “Law of Conservation of Matter”.

29. 1. Whether the reaction will actually occur. Chemical equations can be written for reactions that do not necessarily take place. 2. The speed of a reaction. 3. The pathway atoms or ions take in moving from reactants to products.

30. 1. Write a word equation 2 2. Write a formula equation a) remember naturally occurring diatomic elements: H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2 b) unless otherwise noted, other elements are represented by the element symbol; ex: magnesium = Mg

31. c) remember the formulas for acids: HCl = Hydrochloric Acid HNO 3 = Nitric Acid H 3 PO 4 = Phosphoric Acid CH 3 COOH = Acetic Acid (NOTE: the positive ion (H + ) is at the end) H 2 CO 3 = Carbonic Acid H 2 SO 4 = Sulfuric Acid

32. d) remember the rules for writing formulas for ionic compounds (ions) METALS & NONMETALS!! e) remember the rules for writing formulas for molecular compounds (prefixes) ONLY NONMETALS!!

33. f) remember the formula for water, H 2 O HOH (hydrogen hydroxide)

34. 3. Write a balanced chemical equation by adding coefficients, NOT subscripts (this will require trial and error, the following guidelines may be helpful) a) balance the different types of atoms one at a time b) first, balance the atoms of elements that are combined and that appear only once on each side of the equation

35. c) balance polyatomic ions that appear on both sides of the equation as single units d) balance H atoms and O atoms after atoms of all other elements have been balanced

36. 4. Conduct an atom inventory throughout the process. Be sure to conduct an atom inventory at the end of the process to be certain you have the correct answer. 5 5. Be certain that the coefficients represent the SMALLEST possible whole number ratio of reactants and products.

37. 6. Common problems when balancing equations: a) You must write correct formulas! b) once a correct formula is written, subscripts CANNOT be changed!

38. a) Hydrogen reacts with oxygen to produce water.

39. b) Zinc reacts with hydrochloric acid to produce a solution of zinc chloride and hydrogen gas.

40. c) Aluminum sulfate reacts with calcium hydroxide to form aluminum hydroxide and calcium sulfate.

42. 2 or more substances combine to form one new substance General format: A+ BAB

43. Ex: NH 3 + HClNH 4 Cl 2 Na + C1 2 2 NaCl

44. Synthesis Practice: For each of the following, predict the products and write a word equation. Next, write a formula equation and a balanced chemical equation. Finally, write the type of reaction represented by each chemical equation.

45. a) magnesium + oxygen →

46. b) sodium + fluorine →

47. c) magnesium + fluorine →

48. d) lithium + chlorine → HOMEWORK!!

49. e) barium + oxygen → HOMEWORK!!

50. f) potassium + oxygen → HOMEWORK!!

51. Substances break up or decompose into simpler substances General format: AB Ex: A + B H 2 CO 3 2 Al 2 O 3 H 2 O + CO 2 4 Al + 3 O 2

52. Decomposition Practice: For each of the following, predict the products and write a word equation. Next, write a formula equation and a balanced chemical equation. Finally, write the type of reaction represented by each chemical equation.

53. a) water →

54. b) mercury(II) oxide →

55. c) magnesium chloride → HOMEWORK!!

56. d) silver oxide → HOMEWORK!!

57. One element replaces another in a compound General format: A + BC Ex: Cl 2 + 2 KBr 2 Na + 2 H 2 O AC + B 2 KCl + Br 2 2 NaOH + H 2

58. Single Displacement Practice: For each of the following, predict the products and write a word equation. Next, write a formula equation and a balanced chemical equation. Finally, write the type of reaction represented by each chemical equation.

59. a) aluminum + lead(II) nitrate →

60. b) lithium + water →

61. c) aluminum + sulfuric acid →

62. d) chlorine + potassium bromide →

63. e) fluorine + sodium chloride →

64. f) aluminum + silver nitrate → HOMEWORK!!

65. g) barium + water → HOMEWORK!!

66. h) lithium + hydrochloric acid → HOMEWORK!!

67. Positive and negative ions are exchanged General format: AB + CDCB + AD Ex: Ba(OH) 2 + H 2 SO 4 AgNO 3 + NaCl BaSO 4 + 2 H 2 O AgCl + NaNO 3

68. Double Displacement Practice: For each of the following, predict the products and write a word equation. Next, write a formula equation and a balanced chemical equation. Finally, write the type of reaction represented by each chemical equation.

69. a) potassium iodide + lead(II) nitrate →

70. b) sulfuric acid + sodium hydroxide →

71. c) silver nitrate + sodium phosphate

72. d) nitric acid + potassium hydroxide HOMEWORK!!

73. e) sulfuric acid + potassium hydroxide HOMEWORK!!

74. f) calcium phosphate + acetic acid HOMEWORK!!

75. ____________2) 4 Fe + 3 0 2 ___________3) Cl 2 + 2 NaBr _____________ 2 H 2 O +O 2 2 Fe 2 O 3 2 NaCl +Br 2 Decomposition 1) 2 H 2 O 2 Synthesis Single Displacement

76. _____________4) Zn +H 2 SO 4 Displacement 5 ) Pb(NO ) p ZnSO 4 +H 2 Single Displacement Double ____________5 3 2 +K 2 CrO 4 PbCrO 4 + KNO 3

78. Reaction rate = the rate (speed) of disappearance of a reactant or the rate of appearance of a product in a chemical reaction a) A chemical reaction that takes a long time to happen has a slow reaction rate. b) A chemical reaction that takes a short time to happen has a fast reaction rate.

79. 1) Nature of reactants a) Reactions occur at different rates depending on the reactants. b) ) Some reactions occur almost instantaneously (such as double- replacement reactions). c) Other reactions occur slower.

80. 2) Concentration = a measure of the number of particles of matter per unit volume a) An increase in the concentration of the reactants generally increases reaction rate. b) A decrease in the concentration of the reactants generally decreases reaction rate.

81. 3. Temperature = a measure of the average kinetic energy of the particles in a sample of matter a) An increase in temperature increases reaction rate. b) A decrease in temperature decreases reaction rate.

82. 4. Presence of a catalyst = a substance that increases the rate of a chemical reaction without being permanently changed a) A catalyst will increase reaction rate. b) A catalyst is not permanently changed in a chemical reaction.

83. 1. Assumptions of collision theory: a) Reacting molecules must collide with each other. b) Reacting molecules must collide with sufficient energy. c) Reacting molecules must collide in an orientation that can lead to rearrangement of the atoms.

84. 2) Use collision theory to explain why an increase in concentration increases reaction rate: a) ) At a higher concentration more reactant molecules are present. b) When more reactant molecules are present more frequent collisions occur. c) When more frequent collisions occur there are more chances for molecules to react (so reactions happen faster).

85. 3. Use collision theory to explain why an increase in temperature increases reaction rate: a) Molecules with a higher kinetic energy move faster, collide more often, and have more energetic collisions. b) A higher temperature means that the average kinetic energy of the reacting molecules is increased; at a higher temperature there are more molecules with a higher kinetic energy.

86. c) At a higher temperature there are more frequent collisions giving molecules more chances to react (so reactions happen faster). d) At a higher temperature, more molecules possess enough kinetic energy to react so a higher percentage of collisions result in molecules reacting (so reactions happen faster).