1.
A researcher wants to evaluate how different tire treads affect braking speed. How should she define her control group?
Correct Answer
D. Use of one car during the experiment
Explanation
D. Because the type of car used during the experiment is not manipulated, this is a type of control. See Lesson: Designing an Experiment.
2.
Time is measured using a
Correct Answer
B. Stopwatch.
Explanation
B. A stopwatch is a device used to record time in an experiment. See Lesson: Designing an Experiment.
3.
Which part of the scientific method requires a researcher to create variables?
Correct Answer
B. Testing a hypothesis
Explanation
B. After a hypothesis is formed, variables are created when experiments are designed to test the hypothesis. See Lesson: Designing an Experiment.
4.
An atom has 17 protons, 20 neutrons, and 17 electrons. What is its mass, in amu?
Correct Answer
C. 37
Explanation
C. The mass is determined by adding the numbers of protons and neutrons (17 + 20 = 37). See Lesson: Scientific Notation.
5.
How many neutrons does an atom of silver-109 contain?
Correct Answer
C. 62
Explanation
C. This silver isotope has a mass number of 109. Silver has 47 protons, which contribute 47 to the mass number. To get the number of neutrons, subtract: 109 – 47 = 62. This atom contains 62 neutrons. See Lesson: Scientific Notation.
6.
A neutral atom of aluminum has 13 electrons. How many electrons can be found in each shell in the electron cloud?
Correct Answer
C. 2 in the first shell, 8 in the second shell, 3 in the third shell
Explanation
C. The electrons are found in the lowest possible shells. Only 2 can fit in the first shell, and only 8 can fit in the second shell. Filling those levels accommodates 10 electrons. The remaining 3 electrons will go into the third shell. See Lesson: Scientific Notation.
7.
How many inches are in 35 centimeters?
Correct Answer
B. 13.77
Explanation
B. There are 2.54 centimeters in 1 inch. Dividing 35 by 2.54 converts 35 centimeters to 13.77 inches. See Lesson: Temperature and the Metric System.
8.
How many feet are in a mile?
Correct Answer
D. 5280
Explanation
D. The conversion between feet and mile is a unit conversion in the English system. Within this system, 5,280 feet is equivalent to 1 mile. See Lesson: Temperature and the Metric System.
9.
Which is an example of a biological study?
Correct Answer
B. Evaluate the impact of algal blooms on fish survival
Explanation
B. Biology is the study of life; it examines how living things function and survive. Because fish and algae are living things, this is a biological study. See Lesson: An Introduction To Biology.
10.
What is a control variable?
Correct Answer
A. The variable that is used for comparisons
Explanation
A. The control variable is a standard or constant that is used for comparisons. See Lesson: An Introduction To Biology.
11.
Which trait is used to distinguish living things from nonliving things?
Correct Answer
C. Homeostasis
Explanation
C. Homeostasis is common to all living things, so this trait can be used to differentiate a living thing from a nonliving thing. See Lesson: An Introduction To Biology.
12.
A protein is synthesized in the ribosome. Where does it travel next?
Correct Answer
C. Golgi apparatus
Explanation
C. After a protein is synthesized, it goes to the Golgi apparatus where the protein is further modified and then packaged for transport in the cell. See Lesson: Cell Structure, Function, and Type.
13.
Which organelle is associated with an animal cell?
Correct Answer
D. Golgi apparatus
Explanation
D. An animal cell is a eukaryotic cell, which means it lacks a flagellum. Unlike plant cells, which have chloroplasts and a cell wall, animal cells contain a Golgi apparatus. See Lesson: Cell Structure, Function, and Type.
14.
What cellular process do autotrophs rely on to obtain energy?
Correct Answer
C. pHotosynthesis
Explanation
C. Plant cells are autotrophs that harness energy from the sun and use it to make food. This process of using energy to make food is done with the help of photosynthesis. See Lesson: Cell Structure, Function, and Type.
15.
What must occur as a transition reaction before the citric acid cycle begins?
Correct Answer
C. Pyruvate converts into acetyl coA.
Explanation
C. After glycolysis occurs to make pyruvate, this molecule must be converted into acetyl coA to enter the citric acid cycle in the mitochondrial matrix. See Lesson: Cellular Reproduction, Respiration, and Photosynthesis.
16.
Sister chromatids are formed after chromosomes
Correct Answer
D. Separate.
Explanation
D. During anaphase, the chromosome is pulled apart by spindle fibers that are attached to the centromeres of the chromosome. This causes the chromosome to split into two sister chromatids. See Lesson: Cellular Reproduction, Respiration, and Photosynthesis.
17.
What metabolic process helps a cell yield a large amount of ATP?
Correct Answer
B. Chemiosmosis
Explanation
B. The final process in cellular respiration, the electron transport chain, yields the largest amount of ATP for a cell. Chemiosmosis, which involves the creation of a proton gradient (with the help of NADH and FADH), is part of this step for cellular respiration. See Lesson: Cellular Reproduction, Respiration, and Photosynthesis.
18.
The process that “rewrites” the information in a gene in DNA into a molecule of messenger RNA is called _____.
Correct Answer
C. Transcription
Explanation
C. The process that rewrites the information in a gene in DNA into a molecule of messenger RNA is called transcription. See Lesson: Genetics and DNA.
19.
Once RNA polymerase reaches a stop codon on the DNA molecule, the enzyme detaches from the DNA and releases the RNA molecule
Correct Answer
A. Into the cell for the next stage.
Explanation
A. The RNA molecule is released into the cell for the next stage. See Lesson: Genetics and DNA.
20.
The replication of DNA ends with a twisted strand called a _____.
Correct Answer
C. Double helix
Explanation
C. The replication of DNA ends with a twisted strand called a double helix. See Lesson: Genetics and DNA.
21.
Compare the melting points of three metals: gold (1063°C), lead (328°C), and mercury (-38.9°C). Which of the following statements is true regarding intermolecular forces of these metals?
Correct Answer
A. The intermolecular forces are strongest between atoms of gold.
Explanation
A. Because gold has the highest melting point, it would take more energy to melt it than to melt lead or mercury. If a substance has a relatively high melting point, it is because the forces holding the particles together are relatively strong. See Lesson: States of Matter.
22.
A substance will _____ at the same temperature.
Correct Answer
B. Condense and boil
Explanation
B. Any substance will condense and boil at the same temperature, assuming these processes are carried out under the same conditions. This is the temperature at which the substance transitions between liquid and gas states. See Lesson: States of Matter.
23.
As a substance _____, the particles in the substance get closer together.
Correct Answer
B. Condenses
Explanation
B. As particles condense, the substance turns from gas to liquid. The particles of liquids are closer together than the particles of gas. See Lesson: States of Matter.
24.
The melting point of a substance is an example of a(n) _____ property.
Correct Answer
C. Intensive
Explanation
C. Intensive properties do not depend on the amount of matter that is present. Intensive properties do not change according to conditions. See Lesson: Properties of Matter.
25.
Which of the following is a substance?
Correct Answer
B. Black coffee
Explanation
B. Black coffee is a substance because each sip of the substance contains the same ingredients. See Lesson: Properties of Matter.
26.
Properties that do not depend on the amount of matter that is present are _____ properties.
Correct Answer
C. Intensive
Explanation
C. Intensive properties do not depend on the amount of matter that is present. See Lesson: Properties of Matter.
27.
Which of the following elements will form an ion with a charge of +2 to be stable?
Correct Answer
A. Barium
Explanation
A. Barium is in group 2 and has two valence electrons. Losing those two valence electrons will result in a stable barium ion with a charge of +2. See Lesson: Chemical Bonds.
28.
Which of the following bonds is the most polar?
Correct Answer
B. N-F
Explanation
B. Fluorine is farther to the right in the periodic table, which means it has a higher electronegativity than the other elements in period 2. Therefore, it will pull harder on electrons it shares with nitrogen, forming the most polar bond. See Lesson: Chemical Bonds.
29.
In which compound(s) does a chlorine atom share two electrons with another atom?
Correct Answer
D. SiCl4, PCl3, OCl2, and Cl2
Explanation
D. All four compounds contain chlorine atoms. All chlorine atoms make one bond, sharing two electrons, with another atom. See Lesson: Chemical Bonds.
30.
Which compound involved in the reaction shown below is insoluble in water?
2AgNO3(aq) + CuCl2(aq) → 2AgCl(s) + Cu(NO3)2(aq)
Correct Answer
A. AgCl
Explanation
A. The AgCl is the only compound in this equation that is not in an aqueous solution. Instead, it is a solid that does not dissolve in the solvent in which the reaction is occurring. See Lesson: Chemical Solutions.
31.
If 30 grams of KClO3 is added to 100 grams of water at 0°C, some of the solute remains undissolved. What is the minimum temperature that must be attained to dissolve all the solute?
Correct Answer
B. 70°C
Explanation
B. In the graph, the line for 30 grams of solute crosses the line for KClO3 at 70°C. See Lesson: Chemical Solutions.
32.
Which of the following statements regarding the solubility of Ce2(SO4)3 is true?
Correct Answer
A. Its solubility is higher at 0°C than at 100°C.
Explanation
A. At 0°C, about 18 grams of Ce2(SO4)3 can dissolve in 100 grams of water, and at 100°C, around 4 grams can dissolve. See Lesson: Chemical Solutions.
33.
How do researchers determine the strength of a base?
Correct Answer
A. Determine the pH value
Explanation
A. The pH scale is used to determine the strength of an acid or base. On a scale from 1 to 14, any pH value greater than 7 is basic. The closer the pH is to 14, the stronger the base. See Lesson: Acids and Bases.
34.
What is the pH of a neutral solution?
Correct Answer
C. 7
Explanation
C. A pH scale is used as an indicator and to determine the strength of an acid or a base. Acidic solutions have a pH less than 7, and basic solutions have a pH greater than 7. Neutral solutions have a pH equal to 7. See Lesson: Acids and Bases.
35.
Which would turn litmus paper blue?
Correct Answer
B. KOH
Explanation
B. Basic substances turn litmus paper blue. Because KOH is a strong base, it will turn litmus blue. See Lesson: Acids and Bases.
36.
Correct Answer
A. (–11, 32)
Explanation
A. To multiply a scalar and a vector, multiply each coordinate of the vector by the scalar. Then, add the resultants by adding their respective coordinates:
See Lesson: Nature of Motion.
37.
Correct Answer
B. 0
38.
Vector (2, 6) appears on a graph with its tail at (3, 1). What are the coordinates of its head?
Correct Answer
C. (5, 7)
Explanation
C. The standard form of a vector is the head coordinates minus the tail coordinates. In this case, the head coordinates are unknown. Start by writing an expression for the vector. Let the head coordinates be (x, y), for example.
(2, 6) = (x – 3, y – 1)
Solve the two equations for x and y:
x – 3 = 2
x = 5
y – 1 = 6
y = 7
See Lesson: Nature of Motion.
39.
If a stunt airplane pilot is performing a circular loop and at a certain point feels like she is being pushed upward by a force, what is the direction of the centripetal force?
Correct Answer
B. Down
Explanation
B. The centrifugal force, which is a “ghost force,” is the feeling of being pushed in a certain direction when undergoing rotational motion. The centripetal force, which is a real force, is always in the opposite direction. Thus, if the pilot feels an upward force, the centripetal force must be downward, making answer B correct. See Lesson: Friction.
40.
A ball undergoing projectile motion loses horizontal velocity as it travels. Which factor best explains this deceleration?
Correct Answer
C. Air resistance
Explanation
C. An object undergoing projectile motion maintains a constant horizontal velocity unless some force acts on it. The force in this case is friction due to air resistance. See Lesson: Friction.
41.
The net force on a moving object is due only to friction. Which term best describes the motion of the object?
Correct Answer
A. Linear
Explanation
A. An object subject to no net force will have a constant velocity, meaning its motion is linear. If it is subject only to friction, the net force will be opposite to the velocity, as will the acceleration vector. Although the object will decelerate, its direction of motion will remain the same. Its motion will therefore be linear. See Lesson: Friction.
42.
Which type of wave is mechanical?
Correct Answer
C. Seismic waves
Explanation
C. Mechanical waves involve oscillation of some material, such as water or air. Choices A, B, and D are electromagnetic waves—they can travel in the absence of a material. Seismic waves travel through solids and liquids as a result of geological events. See Lesson: Waves and Sounds.
43.
A straw in a glass of water appears from some angles to bend at the water’s surface. Which wave behavior explains this effect?
Correct Answer
C. Refraction
Explanation
C. The appearance of a bent straw in water is due to the bending of light as it transmits from one material to another when those materials have different indices of refraction—in this case, water and air. Refraction is the wave behavior that explains this effect. See Lesson: Waves and Sounds.
44.
An experimenter has two objects and knows that one of them is positively charged. If that object pushes away the other object when the two are brought into proximity, what can he conclude?
Correct Answer
A. The other object is positively charged.
Explanation
A. Like charges repel, so if the experimenter knows the charge polarity of one object (positive), he knows that the other object has the same charge polarity if they exert a repulsive force on each other. See Lesson: Waves and Sounds.
45.
The impulse on an object is equal to the change in _____ that it causes.
Correct Answer
C. Momentum
Explanation
C. Impulse and momentum and directly proportional. See Lesson: Kinetic Energy.
46.
A volleyball of mass of 2.2 kg leaves the server’s hand at 27 m/s. As the ball crosses above the 2.24 m high net, what kind(s) of energy does the ball possess?
Correct Answer
A. Kinetic and potential
Explanation
A. The volleyball is moving, so it has kinetic energy. It is above ground level, so it also possesses potential energy. See Lesson: Kinetic Energy.
47.
Which term best describes a material that allows electric current to flow freely through it?
Correct Answer
A. Conductor
Explanation
A. A material, such as many metals, that allows current to flow freely through it is called a conductor. See Lesson: Electricity and Magnetism.
48.
A physicist is accelerating ions in a vacuum chamber to examine their behavior. Considering only effects produced by the ions, which of the following will be absent?
Correct Answer
C. Mechanical waves
Explanation
C. Ions are electrically charged particles, so they have electric fields associated with them. Also, since they are accelerating, they produce both magnetic fields and electromagnetic waves. Because they are moving in a vacuum, however, they have no medium in which to produce mechanical waves. See Lesson: Electricity and Magnetism.
49.
A child playing with bar magnets is holding two of them close together such that the south pole of one is facing the north pole of the other. What will happen when the child releases the magnets?
Correct Answer
D. The magnets will draw each other together.
Explanation
D. As with electric charge, like magnetic polarities repel and unlike polarities attract. In this case, the magnets will experience an attractive force that pulls them together. See Lesson: Electricity and Magnetism.
50.
What is the Celsius value for 350°F?
Correct Answer
B. 177