Download 2017 Chemistry Exam Review Compounds and Reactions 1. Know

2017 Chemistry Exam Review
Compounds and Reactions
1. Know the seven diatomic elements.
2. Know how to tell an ionic from a covalent compound.
3. Know how to draw electron dot diagrams for covalent compounds.
4. Know how to draw shared (bonding) electrons for a polar vs. a nonpolar covalent
compound.
5. Know how to balance charge using subscripts for ionic compounds.
6. Know the first ten prefixes for naming covalent compounds.
7. Know how to name and write formulas for ionic and covalent compounds.
8. Know the name for substances on the left and right side of a chemical equation.
9. Describe and be able to recognize the five types of reaction.
10. Know how to balance chemical equations using coefficients.
11. Know what the abbreviations s, l, g, and aq mean in parentheses beside substances.
Stoichiometry
12 Define mole. Define molar mass. Define molar volume of a gas at STP.
13 Be able to determine #atoms of each element in a molecule.
14 Be able to calculate the molar mass of a compound.
15 Be able to calculate the percent composition (by mass) of a compound.
16 Define stoichiometry.
17 Be able to convert back and forth between moles, grams, #atoms/molecules, and liters of
gas at STP.
18 Be able to draw particle diagrams for simple reactions.
19 When given a balanced chemical equation, know how to convert from moles of one
substance to moles of another substance.
20 When given a balanced chemical equation, know how to convert from grams of one
substance to grams of another substance.
21 Be able to calculate %yield from theoretical yield and actual yield.
Thermochemistry
22. What is meant by system vs. surroundings? What is true about energy for a system plus
its surroundings?
23. How does heat relate to thermal energy?
24. In which direction (in terms of temperature) does heat move spontaneously? In terms of
the way molecules collide with each other, why is this so? When does heat stop moving?
25. How does a refrigerator work?
26. Define endothermic vs. exothermic.
27. Define specific heat. Give an example of a common substance with high specific heat.
Low specific heat.
28. Why does a metal feel cool to your skin?
29. How is it good that 60% of your body and 70% of Earth’s surface is water?
30. Define enthalpy (H). Is change of enthalpy positive or negative in an exothermic process?
An endothermic process? Explain.
31. Describe breaking and making bonds in terms of enthalpy (H).
32. Be able to draw a graph of enthalpy for an endothermic reaction and for an exothermic
reaction. In each graph, show the reactants and products, indicate where bonds are broken
and made and label the change of enthalpy (H), including whether it is positive or
negative.
33. Describe a calorimeter and how it works.
34. Describe how we determined experimentally the heat of combustion for a fuel.
35. In a combustion reaction, know how calculate the energy per mole of fuel from the
energy per gram or vice versa? Why is the energy per mole always greater than the
energy per gram?
36. Be able to tell from their chemical formulas which of two fuels produces more energy per
mole and why.
Solutions
37. Define solution in terms of solute and solvent? What is the solvent in an aqueous
solution?
38. Describe and show (with electronegativity values and an electron dot diagram) the
polarity of a water molecule.
39. Draw water molecules to show how, based on their polarity, they cling together. What
properties of water does this “clinginess” cause?
40. Draw water molecules to show how, based on their polarity, they dissolve table salt
(NaCl) by surrounding Na+ cations and Cl- anions.
41. What kind of substance does water tend to dissolve and not dissolve? Why?
42. Be able to write an equation showing the dissociation of an ionic compound.
43. What is a precipitate?
44. Given a precipitation reaction, be able to write the complete and net ionic equations for it
and name the spectator ions.
45. How can the concentration of a solution be increased (two ways)? decreased?
46. Define molarity. What symbol around a substance is used to indicate its molarity?
47. Be able to convert ml to L.
48. Be able to solve molarity problems, where you find molarity, or #mol (or #g) solute, or
#L (or #ml) solution.
Acids and Bases
49. Define acid. Define base.
50. An H+ ion is the same as which subatomic particle? Show how H+ is the same as H3O+ in
an aqueous solution.
51. In a compound containing hydrogen, what makes the hydrogen atom ionizable?
52. Show how an acid (such as HCl) dissociates in water.
53. What is the name for an H3O+ ion? an OH- ion? Which is associated with acids? bases?
54. Define equilibrium.
55. Describe Le Chatelier’s principle and use it to indicate what happens in an equilibrium
reaction when a reactant or product is added or subtracted.
56. In an equation showing the dissociation of an acid, be able to identify the conjugate acid,
conjugate base, and conjugate acid-base pairs.
57. How does an acid or base differ from its conjugate?
58. Define amphoteric. Show how an anion with an ionizable hydrogen (such as HCO3-) can
be amphoteric.
59. What is the expression and the value for Kw? What does the value tell us about the
ionizability of water?
60. In an aqueous solution, how is [H+] calculated from [OH-] (or vice versa)?
61. Define pH. How is it calculated from [H+] or [H3O+]? How is [H+] calculated from pH?
62. What is pH and [H+] for pure water?
63. How is pOH calculated from pH (or vice versa)?
64. What happens to acidity ([H+]) for each pH unit?
65. What is the difference between a strong acid and a weak acid? How do we write the
equations differently for each?
66. What is the difference between a strong acid and a concentrated acid?
67. Draw particle diagrams to show the difference between concentrated strong, dilute
strong, concentrated weak, and dilute weak acids.
68. What does Ka measure? Write the Ka expression for the dissociation of HA (where A- =
any anion).
69. Be able to write the Ka expression and calculate its value from [H3O+], [A-], and [HA].
70. Be able to find the [H3O+] and pH from the Ka and [HA].
71. Be able to complete a neutralization reaction when given the acid and base. Be able to
write the net ionic equation for any neutralization reaction.
72. What is titration?
73. Be able to calculate the molarity of an acid from its volume and the molarity and volume
of a base needed to titrate it.
Gases
74. How are gases different from liquids and solids?
75. How do we think of temperature in terms of molecules? How do we think of pressure?
76. What causes atmospheric pressure? What is air pressure at sea level – in psi? in
atmospheres? What happens to atmospheric pressure as altitude increases and why?
77. Describe three ways to increase the pressure of a gas.
78. Be able to draw circles and dots with arrows to show volume, number of moles, and
temperature for two comparative samples of the same gas.
79. On what scale is temperature measured for the gas laws? Why?
80. What happens to volume in a flexible balloon or to pressure in a rigid container when
temperature rises? Why?
81. What happens to volume in a flexible balloon when external pressure decreases? Why?
82. Describe how to implode a can using air pressure. Why does this work?
83. How and why is a submarine able to rise or sink (without propelling itself)?
84. How is dry pressure determined from total pressure for a gas collected over water?
85. Be able to solve problems using P1V1/T1 = P2V2/T2 and PV = nRT.
Electrochemistry
86. Know how to determine oxidation numbers for elements in molecules and polyatomic
ions.
87. What happens in oxidation? In reduction? How do the two processes combine in a redox
reaction?
88. In a redox reaction, be able to identify which chemicals are oxidized and which are
reduced.
89. How can you tell which of two metals is more active?
90. Which process – oxidation or reduction - occurs at the anode? At the cathode?
91. Describe the half-cell reactions that occur at the anode and cathode of a wet cell (a form
of voltaic cell or battery). What is the purpose of the salt bridge?
92. How is a voltaic cell (a battery) different from an electrolytic cell?
93. Describe how electroplating works. Include what happens at the anode and cathode.