Chemistry Review

Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

____ 1. What are the building blocks of all matter? a. forces c. magnetic fields b. atoms d. kinetic and potential energy

____ 2. Which of the following conversion factors would you use to change 18 kilometers to meters? a. 1000 m/1 km c. 100 m/1 km b. 1 km/1000 m d. 1 km/100 m

____ 3. What are 6 centimeters equal to? a. 600 meters c. 60 millimeters b. d. 600 millimeters of a millimeter

____ 4. A substance that is made up of only one kind of atom is a(an) a. compound. c. element. b. homogeneous mixture. d. solution.

____ 5. What is the symbol for aluminum? a. AL c. Au b. Al d. A

____ 6. The symbol for gold is a. Au. c. Gl. b. Al. d. Go.

____ 7. If a material contains three elements joined in a fixed proportion, it is a(an) a. mixture. c. atom. b. solution. d. compound.

____ 8. Water is a compound because it a. can be broken down into simpler substances. b. always has two hydrogen atoms for each oxygen atom. c. is made of water atoms joined together. d. both a and b

____ 9. Which of the following is malleable? a. glass c. ice b. pottery d. gold

____ 10. Which of the following has the highest viscosity? a. corn syrup c. water b. milk d. orange juice ____ 11. A substance has a melting point of 0ºC and a boiling point of 100ºC. The substance is most likely a. water. c. gold. b. hydrogen. d. table salt.

____ 12. When a physical change in a sample occurs, which of the following does NOT change? a. shape c. volume b. temperature d. composition

____ 13. A substance that has high reactivity a. easily combines chemically with other substances. b. burns in the presence of water. c. displaces dissolved oxygen. d. has a high boiling point.

____ 14. Which of the following is NOT a clue that a chemical change has occurred? a. change in color c. formation of a precipitate b. production of a gas d. change in shape

____ 15. Which of the following is a chemical change? a. ice melting b. ice being carved c. water boiling d. water breaking down into hydrogen and oxygen

____ 16. The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided? a. element c. electron b. atom d. molecule

____ 17. If 2 grams of element X combine with 4 grams of element Y to form compound XY, how many grams of element Y would combine with 14 grams of X to form the same compound? a. 7 grams c. 21 grams b. 14 grams d. 28 grams

____ 18. Which of the following is NOT part of John Dalton’s atomic theory? a. All elements are composed of atoms. b. All atoms of the same element have the same mass. c. Atoms contain subatomic particles. d. A compound contains atoms of more than one element.

____ 19. J. J. Thomson’s experiments provided evidence that an atom a. is the smallest particle of matter. b. contains negatively charged particles. c. has a negative charge. d. has a positive charge. Figure 4-1

____ 20. The diagram in Figure 4-1 shows the results of Rutherford’s gold foil experiment. What caused some of the alpha particles to bounce straight back from the gold foil? a. electrons in the gold atoms c. other alpha particles b. negative charges in the gold atoms d. nuclei in the gold atoms

____ 21. Who provided evidence for the existence of a nucleus in an atom? a. John Dalton c. Democritus b. J. J. Thomson d. Ernest Rutherford

____ 22. Which subatomic particle has a negative charge? a. electron c. neutron b. alpha particle d. proton

____ 23. Which of the following is unique for any given element? a. the number of neutrons c. the number of protons b. the charge on the electrons d. the mass of a neutron

____ 24. The number of protons in one atom of an element is that element’s a. mass number. c. atomic number. b. balanced charge. d. isotope.

____ 25. What can you assume has happened if an electron moves to a higher energy level? a. The atom has become more stable. c. The electron has gained energy. b. The electron has lost energy. d. The atom has lost an electron.

____ 26. Mendeleev arranged the known chemical elements in a table according to increasing a. atomic number. c. number of protons. b. number of electrons. d. mass.

____ 27. In a periodic table, a set of properties repeats from a. element to element. c. column to column. b. group to group. d. row to row. Figure 5-1

____ 28. Figure 5-1 shows a portion of a blank periodic table. Identify the segments labeled A and B. a. A and B are both periods. c. A and B are both groups. b. A is a period and B is a group. d. A is a group and B is a period.

____ 29. Moving from left to right across a row of the periodic table, which of the following values increases by exactly one from element to element? a. isotope number c. atomic mass unit b. atomic number d. mass number

____ 30. The atomic mass of an element is a. the sum of the protons and neutrons in one atom of the element. b. twice the number of protons in one atom of the element. c. a ratio based on the mass of a carbon-12 atom. d. a weighted average of the masses of an element’s isotopes.

____ 31. The unit for atomic mass is a. gram c. pound b. amu d. none of the above

____ 32. Group 7A of the periodic table contains the a. most reactive nonmetals. c. least reactive nonmetals. b. most reactive metals. d. least reactive metals.

____ 33. Compared with Group 2A elements, Group 6A elements have a. more atoms in the ground state. c. more isotopes. b. more valence electrons. d. fewer valence electrons.

____ 34. The tendency of an element to react is closely related to a. its atomic mass. b. attractions between its atoms. c. the number of valence electrons in atoms of the element. d. the ratio of protons to neutrons in atoms of the element.

____ 35. Which halogen is most likely to react? a. Br (bromine) c. I (iodine) b. F (fluorine) d. Cl (chlorine) ____ 36. To keep them from reacting, some highly reactive elements are stored in a. water. c. liquid mercury. b. pure oxygen. d. argon.

____ 37. Typically, atoms gain or lose electrons to achieve a. an exchange of energy. b. ionization. c. a stable electron configuration. d. vaporization.

____ 38. In an electron dot diagram, the symbol for an element is used to represent a. the nucleus. b. the nucleus and all electrons. c. the nucleus and valence electrons. d. the nucleus and all non-valence electrons.

____ 39. Ionization energies tend to a. decrease from left to right across a period. b. increase from the top of a group to the bottom. c. increase from left to right across a period. d. decrease from the bottom of a group to the top.

____ 40. The formation of an ionic bond involves the a. transfer of electrons. c. transfer of protons. b. transfer of neutrons. d. sharing of electrons.

____ 41. Which of the following formulas represents a compound whose molecules contain a triple bond? a. NN c. O3 b. OO d. SO3

____ 42. In the name carbon dioxide, the prefix of the second word indicates that a molecule of carbon dioxide contains a. two carbon atoms. c. a polyatomic ion. b. two oxygen atoms. d. an ionic bond.

____ 43. The substances that undergo change in a chemical reaction are called a. reactants. c. coefficients. b. products. d. elements.

____ 44. Which of the following is a chemical equation that accurately represents what happens when sulfur and oxygen react to form sulfur trioxide? a. Sulfur and oxygen react to form sulfur trioxide. b. S and O2 produce SO3.

c. S + O2  SO3

d. 2S + 3O2 2SO3

____ 45. Which of the following is a balanced chemical equation for the synthesis of NaBr from Na and Br2?

a. Na + Br2  NaBr

b. 2Na + Br2  NaBr

c. Na + Br2  2NaBr d. 2Na + Br2  2NaBr

____ 46. Methane, CH4, burns in oxygen gas to form water and carbon dioxide. What is the correct balanced chemical equation for this reaction?

a. CH4 + O  H2O + CO2

b. CH4 + 4O  2H2O + CO2

c. CH4 + O2  H2O + CO2

d. CH4 + 2O2  2H2O + CO2

____ 47. How many atoms are present in 3 moles of chromium? a. 6.02 1023 atoms c. 1.80 1024 atoms b. 1.80 1023 atoms d. 52.0 atoms

____ 48. How many grams of CO2 are in 2.1 mol of the compound? a. 21.0 g c. 66.0 g b. 44.0 g d. 92.4 g

____ 49. How many moles of He are in 16 g of the element? a. 1.0 mol c. 8.0 mol b. 4.0 mol d. 16 mol

____ 50. The coefficients in a balanced chemical equation always can express the ratio of a. moles of reactants and products. b. volume of reactants and products. c. atoms of reactants and products. d. mass of reactants and products.

____ 51. In a chemical reaction, an iron atom became the ion Fe2+. What happened to the iron atom? a. It lost electrons and was oxidized. b. It lost electrons and was reduced. c. It gained electrons and was oxidized. d. It gained electrons and was reduced.

Completion Complete each sentence or statement.

52. Rust forms because iron and oxygen are highly ______elements.

53. John Dalton observed that elements always combine in the same ratio to form a particular ______.

54. The subatomic particle that J. J. Thomson discovered has a(an) ______charge.

55. Protons and ______are found in the nucleus of an atom.

56. Neutrons and ______have almost the same mass.

57. When an atom gains or loses energy, some of its ______may move between energy levels.

58. The region in which an electron is most likely to be found is called a(an) ______. 59. When all the electrons in an atom are in orbitals with the lowest possible energy, the atom is in its ______state.

60. An atom in which an electron has moved to a higher energy level is in a(an) ______state.

61. In general, a(an) ______metal will be more reactive than an alkaline earth metal in the same period.

62. In an electron dot diagram, each dot represents a(an) ______.

63. The chemical formula for calcium chloride, CaCl2, shows that the compound contains two ______ions for every ______ion.

64. In ionic compounds, the sum of the charges of all the cations and anions must be ______.

65. The molar mass of carbon is ______.

66. A sample of NaCl contains 188 g of the compound. The sample contains ______moles of NaCl.

67. The element ______is always present in a combustion reaction.

68. In a double-replacement reaction, there are two reactants and ______product(s).

Short Answer

69. What is a hypothesis?

70. What is viscosity?

71. What are three common clues that a chemical change has occurred?

72. If an atom has 34 protons and 40 neutrons, what is its mass number?

73. If an atom of tin has a mass number of 118 and an atomic number of 50, how many neutrons are in its nucleus?

74. In a periodic table that included electron dot diagrams, in which column would the diagrams contain more dots— Group 2A (the alkaline metals) or Group 6A (the oxygen family)?

75. In an electron dot diagram of potassium, there is one dot. In an electron dot diagram of silicon, there are four dots. Which element would you expect to be more reactive?

76. A student balanced the chemical equation Mg + O2  MgO by writing Mg + O2  MgO2. Was the equation balanced correctly? Explain your answer. If the equation was not balanced correctly, write the correctly balanced equation.

77. How many moles of nitrogen are contained in 4.20  1024 atoms of nitrogen?

78. How many grams of O2 are in 5.0 mol of the element?

Problem

79. Balance the following chemical equation.

Cu + HNO3  Cu(NO3)2 + NO2 + H2O

80. When iron metal reacts with oxygen, the reaction can form Fe2O3. Write a balanced chemical equation for this reaction, and find the number of moles of oxygen that are needed to form 6 mol of Fe2O3.

Essay 81. A sample of calcium contains calcium-40, calcium-44, calcium-42, calcium-48, calcium-43, and calcium-46 atoms. Explain why these atoms can have different mass numbers but must have the same atomic number.

USING SCIENCE SKILLS

Figure 1-2

82. Analyzing Data What is the slope of the line shown in Figure 1-2?

83. Analyzing Data In Figure 1-2, what is the relationship between mass and volume?

84. Using Tables and Graphs In Figure 1-2, what quantity does the slope represent?

Figure 5-2

85. Using Tables and Graphs Which of the elements shown in Figure 5-2 are in the same period?

86. Classifying Which element in Figure 5-2 is a transition metal? Which is a noble gas? 87. Using Tables and Graphs Which elements in Figure 5-2 have the same number of valence electrons? How do you know?

88. Comparing and Contrasting Based on what you know about elements and the periodic table, compare and contrast the elements beryllium, Be, and iodine, I, which are shown in Figure 5-2.

89. Inferring Find the block labeled ? in Figure 5-2. What is its atomic number? How many valence electrons does it have? Which of the elements shown in Figure 5-2 will it most resemble?

Figure 5-3

90. Inferring Identify the most reactive element shown in Figure 5-3. Explain your answer.

Figure 6-2

91. Using Tables and Graphs Write a description to place in box (2) in Figure 6-2.

92. Using Tables and Graphs What compound name belongs in box (1) in Figure 6-2?

93. Classifying What type of bond belongs in box (3) in Figure 6-2?

94. Classifying What type of bond belongs in box (4) in Figure 6-2?

Substances Compound Remarks A potassium, K, and KI Iodine is a member of the halogen group; iodine, I potassium is an alkali metal.

B carbon, C, and CO2 Carbon and oxygen are both nonmetals. oxygen, O - C Al, O, and H Al(OH)3 OH (hydroxide) is a polyatomic ion.

Figure 6-3

95. Applying Concepts How does the saying “Opposites attract” apply to the bonding in the compound shown in row A of Figure 6-3?

96. Comparing and Contrasting What kind of bond forms between the elements in row B of Figure 6-3? How is this type of bond different from the type of bond that forms between the elements in row A? Chemistry Review Answer Section

MULTIPLE CHOICE

1. ANS: B

2. ANS: A

3. ANS: C

4. ANS: C

5. ANS: B

6. ANS: A

7. ANS: D

8. ANS: D

9. ANS: D

10. ANS: A

11. ANS: A

12. ANS: D

13. ANS: A

14. ANS: D

15. ANS: D

16. ANS: B

17. ANS: D

18. ANS: C

19. ANS: B

20. ANS: D

21. ANS: D

22. ANS: A

23. ANS: C

24. ANS: C

25. ANS: C

26. ANS: D

27. ANS: D 28. ANS: B

29. ANS: B

30. ANS: D

31. ANS: B

32. ANS: A

33. ANS: B

34. ANS: C

35. ANS: B

36. ANS: D

37. ANS: C

38. ANS: D

39. ANS: C

40. ANS: A

41. ANS: A

42. ANS: B

43. ANS: A

44. ANS: D

45. ANS: D

46. ANS: D

47. ANS: C

48. ANS: D

49. ANS: B

50. ANS: A

51. ANS: A

COMPLETION

52. ANS: reactive

53. ANS: compound

54. ANS: negative

55. ANS: neutrons 56. ANS: protons

57. ANS: electrons

58. ANS: orbital

59. ANS: ground

60. ANS: excited

61. ANS: alkali

62. ANS: valence electron

63. ANS: chloride, calcium

64. ANS: zero

65. ANS: 12.0 g/mol

66. ANS: 3.2

67. ANS: oxygen

68. ANS: two

SHORT ANSWER

69. ANS: a proposed answer to a question

70. ANS: Viscosity is the tendency of a liquid to keep from flowing, or its resistance to flowing.

71. ANS: a change in color, the production of a gas, and the formation of a precipitate

72. ANS: 74

73. ANS: 68

74. ANS: Group 6A, the oxygen family

75. ANS: potassium

76. ANS: The equation was not balanced correctly because it was balanced by changing a subscript instead of changing

coefficients. The correctly balanced equation is 2Mg + O2  2MgO.

77. ANS: 6.98 mol

78. ANS: The molar mass of O2 is 16 g/mol, so 5.0 mol of O2 have a mass of 80 g.

PROBLEM

79. ANS:

Cu + 4HNO3  Cu(NO3)2 + 2NO2 + 2H2O

80. ANS:

4Fe + 3O2  2Fe2O3; 9 mol O2

81. ANS: All the atoms of an element have the same atomic number because the atomic number equals the number of protons in an atom. If one of the atoms had a different number of protons, the atom would not be a calcium atom. The mass number can vary because it is the sum of the protons and neutrons, and isotopes of an element can have different numbers of neutrons.

82. ANS: 8.8 g/cm3

83. ANS: a direct proportion

84. ANS: the density of the fluid

85. ANS: Be, C, N, and F

86. ANS: V; He

87. ANS: F and I; they are in the same group in the periodic table.

88. ANS: Beryllium is a reactive metal with two valence electrons. Iodine is a highly reactive nonmetal with seven valence electrons.

89. ANS: 12; 2; beryllium

90. ANS: Rb is the most reactive element shown. Group 1A alkali metals are the most reactive metals, and the reactivity of elements in Group 1A increases from top to bottom.

91. ANS: The atoms of a metal lose one or more valence electrons and form cations. The atoms of a nonmetal gain one or more electrons and form anions. There is an attraction between the oppositely charged ions.

92. ANS: sodium chloride

93. ANS: covalent 94. ANS: metallic

95. ANS: Potassium is a highly reactive metal with one valence electron. Iodine is a highly reactive nonmetal with seven valence electrons. When electrons are transferred from potassium atoms to iodine atoms, there is an attraction between the oppositely charged ions that form. Thus, opposites do attract in an ionic bond.

96. ANS: Covalent bonds form between the nonmetals carbon and oxygen. In a covalent bond, atoms share electrons. When potassium and iodine react, electrons are transferred from potassium atoms to iodine atoms. Ionic bonds form between potassium cations and iodide anions. There is no sharing of electrons in an ionic bond.