Question 1

Why does condensation have a tendency to raise the temperature of a liquid?

Accepted Answer

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Question 2

From the diagram above describing the phase of water relative to temperature and pressure, at which point does water exist in all three phases?

Accepted Answer

The answer of From the diagram above describing the phase...

Question 3

From the diagram above describing the phase of xenon relative to temperature and pressure which is more dense: liquid xenon or solid xenon?

Accepted Answer

From the diagram, we can see that at the same pressure and temperature, the solid phase of xenon has a higher density than the liquid phase. Therefore, solid xenon is more dense than liquid xenon.

Question 4

Why do water drops bead on a freshly waxed surface?

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Question 5

Why does evaporation of a liquid also cool the gas above it?

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Question 6

Why does evaporation cool a liquid?

Accepted Answer

When a liquid evaporates, the molecules with the highest kinetic energy (i.e., the fastest moving) escape from the surface. This means that the remaining molecules have lower average kinetic energy, and therefore, the temperature of the liquid decreases. The escaping molecules also take some kinetic energy with them, which contributes to the cooling effect.

Question 7

Why does sweat cool you off?

Accepted Answer

When sweat evaporates from our skin, it absorbs the heat from our skin, which takes energy from the body and thus cools us off. This is due to the high energy required to change liquid water into water vapor. As the water molecules leave the skin as vapor, they take heat with them, creating a cooling effect.

Question 8

It easier to cool off on a dry day vs. a humid day because the rate of evaporation is ________.

Accepted Answer

The rate of evaporation is greater on a dry day because the air is less saturated with water vapor, allowing sweat to evaporate more easily and quickly. As more sweat evaporates, more heat is lost from the body, making it easier to cool off.

Question 9

From the diagram above describing the phase of water relative to temperature and pressure, is it possible for ice to transform to water vapor (sublime)without ever becoming liquid? At which point on the diagram does this occur?

Accepted Answer

At point D, which is below the triple point, ice can sublime without first becoming liquid. This process is called sublimation, and it occurs when a substance goes directly from a solid to a gas without passing through the liquid phase. Water can be made to sublime at low pressures, as is the case in freeze-drying, a common technique for preserving food and pharmaceuticals.

Question 10

How are pressure and the boiling point of a compound related?

Accepted Answer

As the pressure decreases, the boiling point of a compound decreases because there is less atmospheric pressure to overcome for the liquid to transition into a gas.

Question 11

Does soap increase or decrease water's surface tension?

Accepted Answer

Soap decreases water's surface tension by disrupting the hydrogen bonding between water molecules.

Question 12

Boiling is when the ________.

Accepted Answer

Boiling is defined as the process in which the vapor pressure of a liquid equals the atmospheric pressure, and the liquid changes into its gaseous phase. This occurs when the temperature of the liquid is raised to its boiling point, and the vapor pressure becomes high enough to equal the atmospheric pressure, causing the liquid to vaporize rapidly.

Question 13

From the diagram above describing the phase of xenon relative to temperature and pressure what is the phase of xenon at  and  ?

Accepted Answer

The answer of From the diagram above describing the phase...

Question 14

What happens to the temperature of something while it is boiling?

Accepted Answer

The temperature of something while it is boiling remains constant. This is because boiling is a phase change, where the heat energy is being used to break the bonds between the molecules instead of increasing the temperature. Once all the liquid has turned to gas, any further heat added will increase the temperature of the gas.

Question 15

Which statement best describes what is happening at the surface of liquid water?

Accepted Answer

At the surface of liquid water, there is a dynamic equilibrium where water molecules are constantly evaporating into the gas phase and gas molecules are condensing back into the liquid phase. This involves fast-moving molecules leaving the surface and slower gas molecules being captured, making all the statements correct.

Question 16

Condensation is ________.

Accepted Answer

The answer of Condensation is ________.
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Question 17

What is the boiling temperature of a single water molecule? Does this question make sense?

Accepted Answer

Boiling involves the separation of many molecules, so the concept of boiling is meaningless for a single water molecule.

Question 18

From the diagram above describing the phase of water relative to temperature and pressure, at which point is water boiling?

Accepted Answer

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Question 19

Evaporation is ________.

Accepted Answer

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Question 20

A gold ring cannot sit on the surface of water, but a thin gold wire loop of the same diameter can. Why?

Accepted Answer

The surface area of contact is the same, but the weight of the gold ring is much greater. The gold ring applies a much greater pressure against the surface of the water so that it is able to push through the surface tension.

Quiz 8: How Water Behaves

Why does condensation have a tendency to raise the temperature of a liquid?

From the diagram above describing the phase of water relative to temperature and pressure, at which point does water exist in all three phases?

From the diagram above describing the phase of xenon relative to temperature and pressure which is more dense: liquid xenon or solid xenon?

Why do water drops bead on a freshly waxed surface?

Why does evaporation of a liquid also cool the gas above it?

Why does evaporation cool a liquid?

Why does sweat cool you off?

It easier to cool off on a dry day vs. a humid day because the rate of evaporation is ________.

From the diagram above describing the phase of water relative to temperature and pressure, is it possible for ice to transform to water vapor (sublime) without ever becoming liquid? At which point on the diagram does this occur?

How are pressure and the boiling point of a compound related?

Does soap increase or decrease water's surface tension?

Boiling is when the ________.

From the diagram above describing the phase of xenon relative to temperature and pressure what is the phase of xenon at and ?

What happens to the temperature of something while it is boiling?

Which statement best describes what is happening at the surface of liquid water?

Condensation is ________.

What is the boiling temperature of a single water molecule? Does this question make sense?

From the diagram above describing the phase of water relative to temperature and pressure, at which point is water boiling?

Evaporation is ________.

A gold ring cannot sit on the surface of water, but a thin gold wire loop of the same diameter can. Why?