Question 1

Water is good for putting out fires because it has a very high latent heat of vaporization.

Accepted Answer

Water has a high latent heat of vaporization, which means it requires a significant amount of heat to convert it from a liquid to a gas. When used on a fire, the water absorbs heat and turns into steam, which displaces the surrounding oxygen and helps to extinguish the fire.

Question 2

Air at a temperature of 32°F has a relative humidity of 60%.If the temperature of the same air increases,the relative humidity increases.

Accepted Answer

As temperature increases, the air can hold more moisture. Therefore, if the temperature of the air with a relative humidity of 60% increases, the amount of moisture in the air remains the same, but the air can hold more moisture, leading to a decrease in the relative humidity.

Question 3

specific heat capacity of ice = 2,000 J/kg-°C
latent heat of fusion of water = 334,000 J/kg
specific heat capacity of water = 4,000 J/kg-°C
-The 1 kg block of ice melts into water.The amount of heat absorbed by the ice as it melts is 334,000 J.

Accepted Answer

The statement is correct. The amount of heat absorbed by the ice as it melts is equal to the latent heat of fusion, which is 334,000 J/kg.

Question 4

When water boils,its temperature increases.

Accepted Answer

When water boils, its temperature remains constant at the boiling point until all the water has turned into steam.

Question 5

The dew point is the temperature at which a given humidity equals the saturation density.

Accepted Answer

The dew point is the temperature at which the air becomes saturated with water vapor and any further cooling will result in condensation. It is the temperature at which the given humidity equals the saturation density. Therefore, the statement is true.

Question 6

A liquid cannot be heated simultaneously by conduction,convection,and radiation.

Accepted Answer

A liquid can be heated simultaneously by conduction, convection and radiation. For example, when heating a pot of soup on a stove, the liquid inside is heated through convection (heat transfer through the movement of the liquid), conduction (heat transfer through direct contact with the pot) and radiation (heat transfer through infrared radiation from the stove).

Question 7

Evaporation is when a gas is converted into a liquid.

Accepted Answer

Evaporation is the process of a liquid turning into a gas, not the other way around.

Question 8

When you add heat to ice,its temperature always stays constant.

Accepted Answer

When heat is added to ice, its temperature remains constant only during the phase change from solid to liquid (melting). Before and after this phase change, the temperature can increase.

Question 9

specific heat capacity of ice = 2,000 J/kg-°C
latent heat of fusion of water = 334,000 J/kg
specific heat capacity of water = 4,000 J/kg-°C
-As the ice is melting,the temperature of the ice-water mixture rises by 10°C.

Accepted Answer

When ice melts, it absorbs heat without a rise in its temperature until it becomes water at 0°C. This is due to the latent heat of fusion of water. Therefore, the temperature of the ice-water mixture does not rise during the melting process until all the ice has melted. Once all the ice has melted, the temperature of the water can start rising with the application of further heat.

Question 10

At 96°F the saturation density of air is 0.04 kg/m³.If the weather report says the relative humidity is 90% when the temperature is 96°F,the humidity is 0.036 kg/m³.

Accepted Answer

The saturation density of air at 96°F is 0.04 kg/m³, and if the relative humidity is 90%, which means the air is holding 90% of its maximum water vapor capacity at that temperature, then the actual humidity would be 0.036 kg/m³, which is less than the saturation density. Therefore, the answer is true.

Question 11

Temperature is a measure of heat.

Accepted Answer

The answer of Temperature is a measure of heat....

Question 12

specific heat capacity of ice = 2,000 J/kg-°C
latent heat of fusion of water = 334,000 J/kg
specific heat capacity of water = 4,000 J/kg-°C
-A 1 kg block of ice is removed from a freezer where its temperature was -10°C.The amount of heat absorbed by the ice as it warms to 0°C is 20,000 J.

Accepted Answer

To determine the amount of heat absorbed by the ice, we need to use the specific heat capacity of ice and the change in temperature:
Q = m*c*ΔT
Q = 1kg * 2,000 J/kg-°C * (0°C - (-10°C))
Q = 20,000 J
Therefore, the amount of heat absorbed by the ice as it warms to 0°C is 20,000 J, which matches the given value. So the answer is true.

Question 13

The latent heat of vaporization of water is roughly 10 times the latent heat of fusion of water.The amount of heat required to boil away 1 kg of water is 10 times the amount of heat required to melt 1 kg of ice.

Accepted Answer

This statement is true. The latent heat of vaporization of water is approximately 2260 kJ/kg, while the latent heat of fusion of water is approximately 334 kJ/kg. Therefore, it takes about 10 times more heat to boil away 1 kg of water compared to the amount of heat required to melt 1 kg of ice.

Question 14

The Eiffel tower in Paris is made primarily of iron,whose coefficient of linear expansion is about 10 × 10−⁶/°C.On a cold day when the temperature is −10°C the Eiffel tower is 300 meters tall.Its height on a hot day when the temperature is 40°C is 300.15 m.

Accepted Answer

The Eiffel Tower's height will increase as the temperature increases due to the expansion of the iron material. The change in height can be calculated using the formula ΔL = αLΔT, where α is the coefficient of linear expansion, L is the original length, and ΔT is the change in temperature. Plugging in the given values, we have ΔL = (10 × 10^-5/°C)(300 m)(50°C) = 15 cm. Therefore, the new height on a hot day would be 300 m + 15 cm = 300.15 m, as given in the statement.

Question 15

specific heat capacity of ice = 2,000 J/kg-°C
latent heat of fusion of water = 334,000 J/kg
specific heat capacity of water = 4,000 J/kg-°C
-After the 1 kg block of ice melts,the amount of heat required to raise its temperature to 10°C is 3,340,000 J.

Accepted Answer

The correct calculation for the heat required to raise the temperature of 1 kg of water from 0°C to 10°C is 40,000 J (using the specific heat capacity of water, 4,000 J/kg-°C). The given value of 3,340,000 J is incorrect.

Question 16

Internal energy can only be changed by adding heat

Accepted Answer

Internal energy can be changed by adding heat or doing work on the system.

Question 17

In a steam engine,steam at 140°C in a turbine does work on an external system,and the steam leaves the turbine at 100°C.The efficiency of the steam engine is 5%.The relevant physical principle is the first law of thermodynamics.

Accepted Answer

The relevant physical principle for determining the efficiency of a steam engine is the second law of thermodynamics, which involves the concept of entropy and the Carnot cycle. The first law of thermodynamics deals with the conservation of energy.

Question 18

A piston compresses a gas,while at the same time heat is lost to the surroundings.The temperature of the gas rises.This is governed by the second law of thermodynamics.

Accepted Answer

The second law of thermodynamics states that in any energy transfer process, the amount of useful energy decreases and the amount of disorder or entropy increases. In this scenario, heat is lost to the surroundings, which means the amount of useful energy in the system is decreasing, and the temperature of the gas is rising, which indicates an increase in disorder. Therefore, this scenario goes against the second law of thermodynamics.

Question 19

The specific heat capacity of water is about twice the specific heat capacity of ice.The amount of heat required to boil 1 kg of water is twice the amount of heat required to melt 1 kg of ice.

Accepted Answer

The heat required to boil water (latent heat of vaporization) is much greater than the heat required to melt ice (latent heat of fusion), not just twice.

Question 20

You can increase the temperature of a gas by compressing it.

Accepted Answer

When a gas is compressed, its particles are pushed closer together, which increases the average speed of the particles and therefore increases the temperature of the gas. This is known as adiabatic heating.

Quiz 5: Temperature and Heat