Liquids — Unit test Answers

20 verified answers
1
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Which statement best explains why heating a liquid affects its viscosity?

A
The molecules move faster at higher temperatures and overcome attractions more easily.
B
The molecules move faster at higher temperatures, and the attractions between them increase.
C
The molecules move slower at higher temperatures and overcome attractions more easily.
D
The molecules move slower at higher temperatures, and the attractions between them decrease.
2
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Which is the best example of immiscible liquids?

A
two polar liquids that have high surface tensions
B
a polar liquid and a nonpolar liquid that have low surface tensions
C
two nonpolar liquids that can dissolve into one another
D
a polar liquid and a nonpolar liquid that do not dissolve into one another
3

Water’s molar mass is 18.01 g/mol. The molar mass of glycerol is 92.09 g/mol. At 25°C, glycerol is more viscous than water. Which substance has the stronger intermolecular attraction?

A
glycerol because it has a larger molar mass
B
glycerol because it is more viscous and has a larger molar mass
C
water because it has a lower molar mass
D
water because it is less viscous and has a lower molar mass
4

Malia was able to make a paperclip float on the surface of water. What will most likely happen to the paperclip if a drop of dishwashing detergent is added near it?

A
Soap is a surfactant that increases the intermolecular forces of water allowing the paperclip to continue to float.
B
Soap makes the water less viscous making the paperclip sink.
C
Soap is a surfactant that disrupts the intermolecular forces of water making the paperclip sink.
D
Soap makes the water more viscous allowing the paperclip to continue to float.
5

Which term best describes liquid behavior under pressure?

A
incompressible
B
compressed
C
immiscible
D
surfactant
6

Which molecules would most likely cause a liquid to have the lowest viscosity?

A
large, polar molecules
B
small, nonpolar molecules
C
small, polar molecules
D
large, nonpolar molecules
7

What happens as a result of the kinetic energy of the particles in a liquid being comparable with the intermolecular attractions between the particles?

A
The particles do not move enough to change positions, so the liquid is not compressible.
B
The particles move enough that they separate from one another and take the shape of their container.
C
The particles do not move enough, so they are fixed in place, and the liquid has a fixed volume.
D
The particles move enough that they are not fixed in place, and the liquid can flow.
8

Which postulate of the kinetic-molecular theory applies to the particles of a liquid?

A
They do not move freely but vibrate in a stationary position.
B
They can be compressed, which causes a large change in volume.
C
They have so much kinetic energy that their intermolecular forces are negligible.
D
They have enough kinetic energy to easily slide by each other.
9

Liquids and solids are referred to as “condensed phases” because the attractive forces

A
cause molecules to become stationary.
B
leave little space between the molecules.
C
create large spaces between the molecules.
D
that hold the molecules together are negligible.
10

Which type of substance is water able to dissolve?

A
nonpolar
B
ionic
C
polar
D
ionic and polar
11

Melting can be best described as a process in which molecules

A
lose kinetic energy and move slowly.
B
lose kinetic energy and remain stationary.
C
gain kinetic energy and escape into the atmosphere.
D
gain enough kinetic energy to get past each other.
12

Carla makes a small cardboard boat and floats it in a tub of water. When she adds a drop of dish soap behind the boat, the boat moves forward.Which statement best explains what happened?

A
The soap increased the viscosity of the water behind the boat, allowing the water in front of the boat to flow more easily.
B
The soap reduced the surface tension behind the boat, causing both water molecules and the boat to be pulled forward.
C
The soap increased the kinetic energy of the water molecules behind the boat, causing both the molecules and the boat to move forward.
D
The soap formed an immiscible layer on the water, causing the soap to spread out and push the boat forward.
13

Why are liquids well suited for hydraulics?

A
Liquids have low densities.
B
Liquids are incompressible.
C
Liquids change volume easily.
D
Liquids have few molecules.
14

Glycerol boils at a higher temperature than water. What does this indicate about the attractive forces of glycerol?

A
They are nonexistent.
B
They are the same as those in water.
C
They are stronger than those in water.
D
They are weaker than those in water.
15

What happens when a solid is dissolved into a liquid?

A
Solid particles float toward the surface layer of liquid particles.
B
Solid particles sink down toward the bottom layer of liquid particles.
C
Solid particles become evenly dispersed among liquid particles.
D
Solid particles become suspended in the middle of liquid particles.
16

The particles in water have less mobility than the particles in oxygen. Which statement best explains this observation?

A
Water is always colder than oxygen.
B
Water has a lower density than oxygen.
C
Water particles have a greater kinetic energy.
D
Water particles have strong intermolecular forces.
20

What is produced on the top of a pool of water by the mutual attraction between water molecules?

A
surfactant
B
surface tension
C
a much smaller volume
D
a much higher density

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