Question 1

A post-1982 penny is made with zinc, but its density is actually greater than that of zinc because ________.

Accepted Answer

A)  it is coated with a thin layer of copper, which is more dense than zinc
B)  it is compressed to a smaller volume in the manufacturing process
C)  it has more mass for the same volume
D)  Both A and C are correct D

Question 2

Humidity is a measure of the amount of water vapor in the atmosphere. Why is humidity always very low inside your kitchen freezer?

Accepted Answer

A)  The kitchen freezer is most often sealed off from the atmosphere.
B)  The frost in the freezer absorbs this moisture.
C)  It is not possible for water to be in the gaseous phase at temperatures below 0°C.
D)  At the cold temperatures of your kitchen freezer, water molecules in the vapor phase are moving relatively slowly, which makes it easier for them to stick to inner surfaces within the freezer or to other water molecules. D

Question 3

Imagine that you can see individual molecules. You watch a small collection of molecules that are moving around slowly while vibrating and bumping against each other. The slower moving molecules then start to line up, but as they do so their vibrations increase. Soon all the molecules are aligned and vibrating about fixed positions. What is happening?

Accepted Answer

A)  The sample is being cooled and the material is freezing.
B)  The sample is being heated and the material is boiling.
C)  The sample is being cooled and the material is condensing.
D)  The sample is being heated and the material is melting.
E)  The sample is unchanged. A

Question 4

If you drop a hot rock into a pail of water, the temperature of the rock and the water change until the two are equal. The rock cools and the water warms. Does this hold true if the hot rock is dropped into the Atlantic Ocean?

Accepted Answer

A)  no, because the Atlantic Ocean is so much bigger than a pail of water
B)  no, because the Atlantic Ocean also contains dissolved salts
C)  yes, because heat will continue to flow until they have the same temperature
D)  yes, because the Atlantic Ocean actually contains more energy than does the pail of water

Question 5

Dalton's atomic model gained credibility because ________.

Accepted Answer

A)  atoms are too small to be seen, so no one could prove him wrong
B)  the model worked to explain much about known chemical reactions
C)  people could make gold from common metals
D)  he was elected into the Royal Society

Question 6

Which of the following best describes a liquid?

Accepted Answer

A)  a constant volume but its shape is not defined
B)  a constant shape and a constant volume
C)  does not have a definite shape or a definite volume
D)  will always expand to fill the full volume of its container.
E)  does not deform upon application of pressure

Question 7

Red colored Kool-Aid crystals are added to a still glass of hot water. The same amount of crystals are added to a second still glass filled with the same amount of cold water. With no stirring, which of the following would occur?

Accepted Answer

A)  Without stirring, both glasses will reach uniform color in the same amount of time since they both contain identical amounts of water.
B)  The glass of cold water will reach a uniform red color first since there are no heat convection currents to impede the distribution of the dye.
C)  The glass of hot water will reach a uniform red color first since the higher kinetic energy provides for faster moving molecules to more quickly distribute the dye.
D)  The Kool-aid crystals will never dissolve in either glass until the glasses are stirred.

Question 8

Which of the following is something that is best described as having potential energy?

Accepted Answer

A)  food
B)  wind
C)  running water
D)  a meteorite traveling through the atmosphere
E)  none of the above

Question 9

Which of the following does not describe volume?

Accepted Answer

A)  the weight of a given object
B)  liters
C)  the amount of space a material occupies
D)  a box 20 cm × 20 cm × 20 cm
E)  milliliters

Question 10

A piece of aluminum weighing 10.0 grams is placed into a graduated cylinder that has an initial volume (before immersion)of 35.0 mL. After immersion, the volume on the cylinder reads 38.7 mL. What is the density of the metal sample?

Accepted Answer

A)  2.70 g/mL
B)  0.25 g/mL
C)  0.28 g/mL
D)  0.37 g/mL
E)  3.70 g/mL

Question 11

You take 50 mL of small BB's and combine them with  of large BB's and you get a total of 90 mL of BB's of mixed size. Which of the following statements best explains this?

Accepted Answer

A)  Since the density of the small BB's is less than that of the large BB's their volumes do not add directly to one another.
B)  This is not possible since the Law of Conservation of Volume would be violated.
C)  The total volume actually gets larger since mixing the BB's would leave additional air space because of the difference in size of the two BB sets.
D)  Many of the smaller BB's are able to fit within the pockets of space that were empty within the  of large BB's.

Question 12

A supersonic airplane heats up considerably when traveling through the air at speeds greater than the speed of sound. As a result, the airplane during supersonic flight is longer than when it is at rest on the ground. Offer an explanation for this length change from a submicroscopic perspective.

Accepted Answer

A)  The engines on the supersonic plane are so powerful that they cause the plane's metal skin to stretch during accelerations.
B)  Materials expand as they are heated.
C)  Atmospheric air molecules hit the supersonic plane at great velocities causing the atoms of the planes metal skin to start moving faster.
D)  Both A and B are correct.

Question 13

A block of wood that weighs 10. g is immersed in water. The total amount of water displaced is 12 mL. What is the density of the block of wood?

Accepted Answer

A)  0.83 g/mL
B)  1.2 g/mL
C)  0.83 mL/g
D)  12 g/10 mL
E)  120 g/mL

Question 14

What type of phase change does the following figure best describe?

Accepted Answer

A)  melting
B)  condensation
C)  evaporation
D)  freezing
E)  none of the above

Question 15

Someone wants to sell you a piece of gold that they say is nearly pure. Before buying the piece, you measure its mass to be 52.3 grams and you find that it displaces 4.16 mL of water. Calculate its density and assess its purity given the fact that pure gold has a density of 19.3 g/mL.

Accepted Answer

A)  The piece of gold is about 65 percent pure.
B)  The piece of gold is only about 12.6 percent pure.
C)  The piece of gold is only about 8 percent pure.
D)  Not enough information is given to calculate the purity, but enough information is given to let you know that the piece is far from pure.

Question 16

Assuming temperature remains constant, what happens to the density of a gas as the gas is compressed into a smaller volume?

Accepted Answer

A)  The density of the gas decreases along with the decreasing volume.
B)  The density of the gas increases along with the decreasing volume.
C)  The density of the gas stays the same because it is an intrinsic property of a material.
D)  The density increases because of an increase in mass.

Question 17

If all of the above images represents the same material, which has the highest temperature?

Accepted Answer

A)  A because heat causes an increase in density.
B)  B because the gas has expanded.
C)  C because neither A or B are plausible.
D)  All have same temperature.

Question 18

A TV screen looked at from a distance appears as a smooth continuous flow of images. Up close, however, we see this is an illusion. What really exists are a series of tiny dots (pixels). This is similar to a chemist's view of matter in that ________.

Accepted Answer

A)  the fundamental particles of matter can also be seen when looked at closely with a magnifying glass
B)  on the submicroscopic level, chemist's find that matter is made of extremely small particles, such as atoms and molecules.
C)  anything that a chemist can see, touch, hear, smell, or taste is an illusion
D)  elements are made up of only three basic types of matter

Question 19

Why is it not possible for the scanning probe microscope (SPM)to make images of the inside of an atom?

Accepted Answer

A)  The most representative "image" of the inside of the atom would be a picture of empty space.
B)  The SPM works by passing a current across a tiny gap between the tip of an ultrathin needle and the surface being studied. No gap, no image.
C)  The SPM ultrathin needle itself is made of atoms and so is not tiny enough to pierce through an atom much like a sewing needle can pierce into a Ping-Pong ball.
D)  All of the above are reasonable answers.

Question 20

How does Aristotle's model of matter explain why the air over a flame is always moist?

Accepted Answer

A)  Aristotle's model of matter explains that moisture in the air draws heat out of the flame.
B)  Aristotle's model of matter explains that moisture counters heat since water counters fire.
C)  Aristotle's model of matter would explain quite the opposite and predict the air above the flame would become dry.
D)  Aristotle's model does not deal with the concept of air over a flame.

Exam 2: Particles of Matter