Physics HW 17

How does the freezing point of a liquid compare with its melting point? - Freezing point is greater than melting point for a pure substance. - Freezing point is less than melting point for a pure substance. - Both freezing point and melting point are the same for a pure substance.

- Both freezing point and melting point are the same for a pure substance.

What happens when you heat ice that is at 0∘C? - The temperature stays constant forever. - The temperature increases forever. - The temperature stays constant until all the ice is melted. - The temperature increases until all of the ice is melted

- The temperature stays constant until all the ice is melted.

In an insulated container, liquid water is mixed with ice. What can you conclude about the phases present in the container when equilibrium is established? - There would be ice only. - There would be liquid water only. - There would be both ice and liquid water. - There is no way of knowing the phase composition without more information.

- There is no way of knowing the phase composition without more information.

A boy scout will be burned more severely by - 100 g of water at 100°C - 100 g of steam at 100°C - both about equally - neither of these

100 g of steam at 100°C

The calories needed to change 10 grams of ice at 0°C to steam at 100°C is - 7200. - 8000. - 6400. - 6200. - none of the above

7200

How does using a pressure cooker affect the amount of internal energy in the water inside the pressure cooker, and why? - It decreases the amount of internal energy because it does not prevent the water from boiling. - It increases the amount of internal energy because it does not allow the heat to boil the water. - It does not affect the amount of internal energy, because the internal energy is affected only by how much heat is provided externally.

It increases the amount of internal energy because it does not allow the heat to boil the water.

What happens to water at room temperature if you decrease the atmospheric pressure around it? - The water will immediately freeze. - The water will keep boiling. - It will neither freeze nor boil. - It will first boil and then freeze.

It will first boil and then freeze.

How does the pressure exerted by bubbles in the water compare with the atmospheric pressure when the temperature of water in an open pressure cooker is below 100∘ C and when it equals 100∘ C? - The pressure exerted by the bubbles exceeds the atmospheric pressure both below 100∘ C and at 100∘ C. - The pressure exerted by the bubbles is equal to the atmospheric pressure both below 100∘ C and at 100∘ C. - The pressure exerted by the bubbles exceeds the atmospheric pressure below 100∘C and equals the atmospheric pressure at 100∘ C. - The pressure exerted by the bubbles is less than the atmospheric pressure below 100∘ C and equals the atmospheric pressure at 100∘C.

The pressure exerted by the bubbles is less than the atmospheric pressure below 100∘ C and equals the atmospheric pressure at 100∘ C.

What happens when you heat water that is at 0∘C? - The temperature increases forever. - The temperature increases until it reaches 100∘C. - The temperature does not change.

The temperature increases until it reaches 100∘C.

What happens when you heat ice that is at -40∘C? - The temperature increases forever. - The temperature stays constant. - The temperature increases until the ice reaches its melting point.

The temperature increases until the ice reaches its melting point.

What happens when you heat water that is at 100∘∘C? - The temperature increases forever. - The temperature increases until all of the water is boiled. - The temperature stays constant forever. - The temperature stays constant until all the water is boiled.

The temperature stays constant until all the water is boiled.

When a solid melts, energy is - absorbed by the solid. - released by the solid. - both of these - neither of these

absorbed by the solid

When vapor transforms to a plasma, energy must be - absorbed by the vapor. - released from the vapor. - both of these - neither of these

absorbed by the vapor.

The main difference between a fog and a cloud is - water vapor content - temperature - density of vapor - seeding - altitude

altitude

The final temperature of the water is __________. - higher than T1 - between T1 and T2 - lower than T2

between T1 and T2

You are mixing water with ice in an insulated container. The temperature of the ice is initially below its freezing point. The following are given: the amount of heat absorbed by the ice if heated to its melting point: 400 JJ, the amount of heat absorbed by the ice if it all melts (which includes the heat needed to bring the ice to its melting point): 2100 JJ, the amount of heat given off by the water if cooled to its freezing point: 1800 JJ, and the amount of heat given off by the water if it all freezes (which includes the heat needed to bring the water to its freezing point): 5200 JJ. Based on this information, at equilibrium, which phases are present? - ice only - water only - both ice and water

both ice and water

A heat pump can - warm an environment. - cool an environment. - both of these - neither of these

both of these

Water can be turned to ice by - extracting energy - lowering the surrounding air pressure - both of these - neither of these

both of these

What occurs in a pan of water placed outdoors on a warm day? - evaporation - condensation -both of these - neither of these

both of these

You can add heat without raising temperature to - ice - boiling water - both of these - neither of these

both of these

Ice is put in a cooler to cool the contents. To speed up the cooling process, the ice can be - broken into smaller pieces. - wrapped in newspaper. - kept away from the food. - drained of water periodically. - none of the above

broken into smaller pieces.

A geyser such as Old Faithful in Yellowstone Park is similar to a - coffee percolator - vat of molten lead - vacuum bottle - teakettle - canteen.

coffee percolator

Double-pane windows contain nitrogen rather than air to prevent - heat flow - condensation - gas escape - thermal conduction

condensation

We feel uncomfortably warm on a muggy day because water molecules are - evaporating from our moist bodies - evaporating and condensing on our bodies at the same rate - condensing on our bodies - none of the above

condensing on our bodies

When a geyser erupts, pressure at its bottom - decreases - is unaffected - increases - all of the above - none of the above

decreases

To melt ice, add - energy - time - force - temperature.

energy

Wrapping a hot potato in aluminum foil significantly reduces the rate at which it cools by - condensation - melting - evaporation - conduction

evaporation

Compared with sea-level cooking, in cooking eggs by boiling in mountain regions you should boil the eggs - with a hotter flame - for a longer time - for a shorter time - all of the above - none of the above

for a longer time

The temperature at which water freezes is the same as the temperature at which - ice melts - water boils in a pressure cooker - both of these - neither of these

ice melts

You are mixing water with ice in an insulated container. The temperature of the ice is initially below its freezing point. The following are given: the amount of heat absorbed by the ice if heated to its melting point: 6400 JJ, the amount of heat absorbed by the ice if it all melts (which includes the heat needed to bring the ice to its melting point): 14,100 JJ, the amount of heat given off by the water if cooled to its freezing point: 1800 JJ, and the amount of heat given off by the water if it all freezes (which includes the heat needed to bring the water to its freezing point): 5200 JJ . Based on this information, at equilibrium, which phases are present? - ice only - water only - both ice and water

ice only

Rank the boiling-water temperatures in different locations. sea level Denver, CO (the "mile-high city") Death Valley

l: Death Valley sea level s: Denver, CO (the "mile-high city")

Rank the energies needed for different phase changes for equal amounts of H2O. from boiling water to steam from ice to ice water from ice water to boiling water

largest: from boiling water to steam from ice water to boiling water smallest: from ice to ice water

Foreign ions introduced to water - raise the freezing point of water - do not affect water's freezing point - lower the freezing point of water

lower the freezing point of water

To turn 1 gram of boiling water to steam requires - almost as much energy as changing 1 gram of 0°C water to the boiling point. - as much as increasing 1 kilogram of 95°C water to the boiling point. - more energy than needed to turn 1 gram of absolute-zero ice to the boiling point. - none of the above

more energy than needed to turn 1 gram of absolute-zero ice to the boiling point.

In mountain regions, food cooked in boiling water cooks slower than when cooked at sea level. If the temperature beneath the pot of boiling water is increased, the food will cook - faster - slower still - both of these - neither of these

neither of these

When you walk barefoot on red-hot wooden coals it is best if - you impress your friends by carrying away bits of wood between your toes. - you walk slowly to demonstrate your courage. - no pieces of metal are among the coals. - all of the above - none of the above

no pieces of metal are among the coals.

Dean teaches that the phenomenon of regelation is due to the - high specific heat of water - open-structured nature of ice crystals - freezing point of water - melting point of ice.

open-structured nature of ice crystals

In one word, how can water in the power plant of a nuclear submarine far exceed 100°C? - pressure - evaporation - conductivity - condensation - vaporization

pressure

Increased air pressure on the surface of hot water tends to - promote boiling - prevent boiling - both of these - neither of these

prevent boiling

An inventor discovers a harmless and tasteless salt, which when added to water changes its boiling point. The market value for this salt will be better if the salt - lowers the boiling point of water - either raises or lowers the boiling point, as the food would be cooked either way. - raises the boiling point of water - none of the above

raises the boiling point of water

When fast-moving water molecules collide they tend to - rebound without sticking - stick - both of these - neither of these

rebound without sticking

When a gas is changed to a liquid, the gas - releases energy - absorbs energy - both of these - neither of these

releases energy

When heat is added to boiling water, its temperature - remains unchanged - increases - decreases - none of the above

remains unchanged

Morning dew on the grass is a result of - the open-structured form of water crystals - evaporation of water - air pressure on water vapor - slow-moving water molecules sticking to one another.

slow-moving water molecules sticking to one another.

The most responsible factor for whether a substance takes the phase of solid, liquid, gas, or plasma is its - temperature. - atomic shell configuration. - composition. - none of the above

temperature

Rapid evaporation of hot water can lead to - the formation of ice. - superheated steam. - both of these - neither of these

the formation of ice.

The reason that evaporation is a cooling process is - radiation of heat during the process. - due to conduction and convection. - the more energetic molecules escape the liquid. - all of the above - none of the above

the more energetic molecules escape the liquid

A hot dog pants -to provide more oxygen into its lungs. - to impress dogs of the opposite sex. - to enable evaporation in its mouth and bronchial tract. - none of the above

to enable evaporation in its mouth and bronchial tract.

What do you use a pressure cooker for? - to cause boiling and cooling - to cause boiling and prevent cooling - to prevent boiling and cooling - to prevent boiling and cause cooling

to prevent boiling and cooling

In a heat pump, cooling is accomplished when - condensation occurs in its coils. - vaporization occurs in its coils. - both of these - neither of these

vaporization occurs in its coils.

When ice crystals form in clouds, the surrounding air - warms. - cools. - neither of these

warms

In an insulated vessel, a quantity of hot water at temperature T1 is mixed with a different quantity of cold water at temperature T2. After equilibrium is established, the vessel contains __________. - steam only - ice only - water and ice - water only

water only

You are mixing water with ice in an insulated container. The temperature of the ice is initially below its freezing point. The following are given: - the amount of heat absorbed by the ice if heated to its melting point: 400 JJ, - the amount of heat absorbed by the ice if it all melts (which includes the heat needed to bring the ice to its melting point): 2100 JJ, the amount of heat given off by the water if cooled to its freezing point: 2400 JJ, and - the amount of heat given off by the water if it all freezes (which includes the heat needed to bring the water to its freezing point): 5200 JJ. Based on this information, at equilibrium, which phases are present? - ice only - water only - both ice and water

water only