APS PRACTICE FINAL EXAM ANSWERS AND EXPLAINATIONS
1. (C) Theories are based on many scientists’ work over a long period of time.
2. (B) Only a new discovery can change a theory because it means that we know more than we did
before.
3. (C) This is the process that scientists follow.
4. (B) Observations are a part of data and a hypothesis must be made before it can be tested.
5. (C) Always test things!
6. (A) No experiment can fail because you have still learned something- even if it means the way you
did something is unsuccessful.
7. (B) Moles measure the amount of matter, ampere measures current, and a degree is just an
increment of something.
8. (B) Mega = 106
9. (D) Centi = 10-2
10. (C) Use King Henry
11. (D) Weight is the amount gravity pulls on an object, mass is the amount of matter. Do not
confuse the terms!
12. (B) Locate 5°C on the y-axis and follow the spot straight across until you hit the line. From that
spot, read down until you hit the x-axis.
13. (C) Negative exponents mean you should move the decimal point to the left.
14. (C) Scientific notation requires a number to be between 1 and 10. Then count how many times
you’ve moved the decimal, NOT the number of zeros.
15. (A) 4.56 has 3 sig figs.
16. (B) 2.5 has 2 sig figs.
17. (B) This is the definition of matter.
18. (A) This is the definition of chemistry.
19. (C) This is the definition of an element. Elements are combined to make compounds.
20. (D) Hydrogen and oxygen combine chemically to make the compound water.
21. (C) Salt water is a homogeneous mixture.
22. (D) There are 2 hydrogens, 1 sulfur and 4 oxygens. 2+1+4=7.
23. (B) Carbonated drinks (sodas) have carbon dioxide gas mixed into the liquid.
24. (A) Solids retain their shape regardless of what they are in. Liquids and gases take the shape of
their containers.
25. (A) Choices B and C are chemical properties. Density is physical.
26. (C) All of the other choices are physical properties.
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27. (B) 𝐷 = 𝑉
28. (A) All other choices are chemical changes.
29. (C) Sublimation is solid to gas, condensation is gas to liquid, and freezing is liquid to solid.
30. (B) Evaporation is liquid to gas, melting is solid to liquid.
31. (D) Liquids and gases are considered fluids because their particles can move around. Solid
particles cannot.
32. (C) Liquid keep their volume but change their shape depending on the container.
33. (B) Temperature is the average kinetic energy. Kinetic = motion.
34. (B) Skip this question
35. (D) You need to add heat in order for ice to melt.
36. (D) See #s 29 & 30.
37. (D) Dalton realized that atoms of each element are exactly the same because they always make
the same compounds when combined with other elements.
38. (B) Protons and neutrons are found in the nucleus. Protons have a positive charge.
39. (B) Electrons have a negative charge.
40. (A) Bohr’s model has different energy levels with electrons inside. Drawn out, it looks like a solar
system.
41. (C) Electrons travel around the nucleus in different energy levels.
42. (A) The periodic table is arranged by atomic number, which is the number of protons. There are
three instances on the periodic table where mass decreases instead of increasing.
43. (C) Groups (columns) on the periodic table contain elements with the same number of valence
electrons (outermost electrons)
44. (B) The valence electrons are the electrons that interact with other atoms because they are on the
outside. Therefore, they determine how an element will behave chemically.
45. (D) Ions are atoms that have gained or lost an electron. Ionization is the process that makes ions.
46. (C) Atomic number is equal to number of protons.
47. (D) Alkali metals are found in group 1 on the periodic table.
48. (C) Alkali metals are found in group 1 on the periodic table, meaning they only have one valence
electron. They will easily lose this electron.
49. (B) Noble gases exist alone as they do not easily combine with anything. Transition metals make
compounds with bright colors. They are not reactive at all but are not necessarily rare in nature.
50. (A) Halogens are nonmetals which means that they gain electrons and make negative ions.
Choice B describes metals. C and D are nonsense.
51. (B) A mole describe the amount of matter at hand.
52. (A) Avogadro’s number, 6.022 x 1023, is the number of particles in one mole of a substance.
53. (D) Molar mass is the same thing as gram formula mass. It is the mass of one mole of atoms.
32𝑔
54. (B) 0.75 mol × 1 mol = 24 𝑔
55. (A) 85.5 g ×
1 mol
19 g
= 4.5 mol
56. (B) Chemical bonds hold ions together. Electric currents refer to the movements of charged
particles, physical bonds is not a real term in this class, nuclear forces hold protons and neutrons
together in the nucleus.
57. (C) Compounds must always follow the same formula every time. Water is always an oxygen
with two hydrogens. Mixtures can be combined in any ratio. You can make saltwater with any
amount of salt and any amount of water.
58. (A) There are no subscripts next to either element so there is only one of each of them. You don’t
write the one just as you don’t write 1x in math class.
59. (D) The 12 after the C shows that there are 12 carbon atoms. None of the other choices are
correct.
60. (A) Solid particles are most strongly attracted to each other which is why they are so close
together. To answer this question, ignore the actual compound and just look at the state of matter.
61. (B) Gas particles are so far away from each other that they cannot be as attracted as liquid and
solid particles. This is why they are free to take up so much space.
62. (C) Opposites always attract therefore the answer cannot be B or D. A is wrong because the
nucleus is positive.
63. (A) Ionic bonds form between metals and nonmetals. Metals are positive ions, nonmetals are
negative ions.
64. (C) Covalent bonds form between nonmetals.
65. (A) Covalent bonds form when two atoms share electrons with each other. Metallic bonds happen
between metals, Ionic bonds form between ions, and polyatomic bonds are not a real thing.
66. (C) Di means 2 and tetra means four.
67. (B) The roman numerals always refer to the oxidation state of the metal which means that this
iron is Fe3+. Roman numerals are used only for transition metals that have more than one oxidation
state.
68. (B) See above.
69. (C) See above.
70. (A) In order to name this, we need to know what the oxidation state of each element is. Bromine
will always be -1 in an ionic compound. If there are 2 bromines, that means there is a total negative
charge of -2. Because the charge of a compound must always add to zero, the total positive charge
must be +2. Because there is only one copper, it must be +2.
71. (D) Follow the same reasoning above except using the information that oxygen is -2.
72. (B) Carbon has four valence electrons and needs four more to get to 8. It will make four bonds to
get those other four electrons.
73. (A) Changes in appearance can signal that a chemical change has taken place.
74. (D) In chemical reactions, atoms are changed from one compound to another. They cannot be
created nor destroyed because of the law of conservation.
75. (A) Exothermic means that heat has been given off by a reaction. They will give the heat to what
surrounds it.
76. (B) Endothermic reactions take in heat or need heat to get started. The heat will come from the
surroundings.
77. (D) In a synthesis reaction, two reactants combine to form one larger one.
78. (B) Decomposition breaks one reactant down into two or more parts. In digestion, food particles
are broken down into smaller pieces.
79. (C) This is the only choice that actually has the same elements in it.
80. (C) You can only change coefficients, not subscripts.
81. (B) Read the reaction like you would read a recipe. The reaction states that you need 2 mol of
water to produce the products listed. 2 mol of H2 will be produced according to this.
82. (C) This problem starts with double the amount of reactant so you will produce double the amount
of product. Choice C is the only one that is double.
83. (D) This problem starts with 5 times the amount of reactants so you will produce five times the
amount of products. 2 x 5 = 10.
84. (B) The equation is given to you balanced so you just need to see how many moles of each you
need.
85. (C) The law of conservation states that matter can neither be created nor destroyed which means
that the total before the reaction must be the total after.
86. (C) Speed is equal to distance divided by time. You must know both to calculate it.
87. (B) An object at rest is not moving.
88. (A) Velocity is a vector which means it must have a direction with it. Speed is velocity without a
direction.
89. (C) This is the formula.
90. (C) You are dividing m/s by s which results in m/s2.
91. (B) Negative slopes mean that something is slowing down. A positive slope means that
something is speeding up. No slope means that the object is not accelerating.
92. (A) Force is needed to change the motion of an object. Inertia is the tendency of an object to
resist changes in motion. Momentum is the amount of motion and deceleration is slowing down.
93. (D) Forces add up to the net force. Forces in opposite directions cancel each other out.
94. (C) Force balance out when they add to zero or cancel each other out. Unbalanced forces do not
add to zero.
95. (D) The forces are unbalanced because the rope is moving the direction of the stronger team. If
the forces were balanced, the rope would not be moving.
96. (A) Friction always goes against motion and happens anytime two objects touch each other.
97. (A) The parachutist floats gently to the ground because the parachute slows him down due to
friction between the parachute and the air.
98. (D) Motion is always relative- you must compare it to a specific point.
99. (A) p= mv
100. (D) All of the following involve speed so they are all zero.
101. (B) p=mv. p = (10.0 kg)(6.0 m/s) = 60.0 kgm/s.
102. (C) You must use meters and seconds and kilograms.
103. (C) Weight is due to gravity, mass is due to matter.
104. (D) They have the largest masses, therefore they will have the greatest gravitational attractions.
105. (B) F = ma
106. (A) Measure force in Newtons
107. (A) First convert pounds into kilograms and then use F=ma to find the force.
108. (C) In free fall, an object accelerates due to gravity.
109. (B) Reaction forces are equal but opposite.
110. (C) W = Fd. If there is no distance, there is no work.
111. (D) Work can be measured in all of the above if you convert.
112. (D) W =Fd. Calculate for each option to determine which has the greatest work.
113. (B) W =Fd = (55 N)(4 m)
114. (A) Power is measured in watts.
115. (D) P = (Fd)/t
116. (A) Machines are used because they make it easier to do work.
117. (C) Work isn’t always equal to energy because some energy is lost because of friction.
118. (C) PE= mgh
119.(D) Each choice is a variable in the equation to calculate potential energy.
120. (B) KE = (1/2)mv2
121. (C) Mechanical = potential and kinetic energy
122. (C) Nuclear energy is in the nucleus, light energy comes from light, and kinetic energy comes
from motion.
123. (A) Potential and kinetic energy have an inverse relationship. As one increases, the other
decreases.
124. (C) W = Fd
125. (C) The others are false.
126. (A) Charges move through conductors. They do not move through insulators.
127. (D) Resistance controls how bright a light will appear. Lower resistance = brighter.
128. (C) Resistance is measured in ohms.
129. (B) I = V/R
130. (A) Potential difference = voltage. V = IR
131. (A) R = V/I
132. (B) V = IR