Chapter 8: Heat

if you triple the absolute temperature of an object, it will radiate energy

81 times faster

good absorbers of radiation

a good emitter of radiation

in the mountains. water boils at

a lower temperature than at sea level

if air were a better conductor that it is, at nighttime the earth would be

considerably colder

if your hands are being warmed by holding them above a flame, then the primary form of heat transfer is which process?

convection

Ice is put in a cooler in order to cool the contents. To speed up the cooling process, the ice can be

crushed

When a volume of air is compressed, its temperature

decreases

when water freezes, the entropy of the water

decreases

a good reflector of radiation is a

poor absorber of radiation

a good heat conductor is a

poor insulator

Increased air pressure on the surface of hot water tends to

prevent boiling

If holding hands to one side of a flame, the predominant form of heat transfer is what process?

radiation

if you hold your hands to one side of a flame, the predominant form of heat transfer that you will experience is

radiation

the planet earth loses heath mainly by

radiation

a refrigerator

removes thermal energy from inside the refrigerator

suppose you are served coffee at a restaurant before you are ready to drink it. In order for it to be the hottest when you are ready for it, you should add cream

right away

the primary reason why a sandy beach gets so hot on a sunny day is becuase

sand has a small specific heat

is it possible to transfer heat from a cold reservoir to a hot reservoir?

yes, but work will have to be done

Which would burn the most? A) 100g of water at 100 degrees C B) 100g of steam at 100 degrees C C) both would be equally damaging

(b) 100g of steam at 100c

Compared to a glass of ice water with ice in it, a glass of plain ice-cold water without ice on a warm day will warm up

FASTER

the kelvin temperature scale has the same size degree as the ___ scale and its zero is ___ lower

celsius / 273

hydrogen and oxygen molecules in a sample gas have the same temperature. This means the hydrogen molecules, on average, have the same

kinetic energy, but more speed

if a poor absorber of radiation were a good emitter, its temperature would be

less than its surroundings

evaporation is a cooling process because

more energetic molecules are able to escape the liquid

Food cooked in boiling water in the mountains cooks more slowly than cooked at sea level. If the temperature under the pot is increased, the food will cook

neither faster or slower

sea breezes on a beach are attributed to a difference between land and water with respect to what property?

specific heat

If molecules in a sample of gas moved so they completely missed each other, the gas's temperature would

stay the same

When heat is added to boiling water, its temperature

stays the same

at what temperature is water most dense ?

4 degrees Celsius

objects that radiate relatively well

absorb radiation relatively well

when a solid is changes to a liquid phase, the solid

absorbs energy

saturation occurs in air when the

air contains as many water molecules as it can contain at a given temperature

if you were caught in freezing weather with only a candle for heat, you would be warmer in

an igloo

heat engines, such as an automoblie engine, are more efficient when run

at high temperatures

as entropy of a system increases, energy in the system

becomes more diluted

Cold water will warm to room temperature faster in a

black pot verses a silver pot

hot water will cool to room temperature faster in a

black pot verses a silver pot

If you want to cook eggs by boiling them while in the mountains, then compared to sea level cooking, you should

boil the eggs for a longer time

a heat pump

can acts as heater, an air-conditioner, though only works wells in moderate climates, but can also by a reversible heat engine

An object will normally be a net radiator of energy when its thermal energy is...

can't answer, because thermal energy is not temperature

Consider a steaming aluminum soda-pop can that contains a small amount of boiling water. When it is quickly inverted into a bath of cooler water the can is dramatically crushed by atmospheric pressure. This occurs because the pressure inside the can is rapidly reduced by

condensation of steam inside

by what primary heat transfer mechanism does one end of a metal spoon become hot when the other end is place in boiling water

conduction

the space between the inner walls of a thermos bottle is evacuated to minimize heat transfer by

conduction and convection

a substance can absorb heat energy by the process of

convection

warm air raises because faster moving molecules tend to move to regions of less

density and pressure

the second law of thermodynamics leads us to conclude that

disorder in the universe is increasing with the passage of time

The work output of a perfectly constructed heat engine

equals the difference between its heat intake and heat exhaust

if a volume of air is warmed, it

expands

energy transfer by convection is primarily restricted to

fluids

steam burns are more damaging than burns caused by boiling water because steam

gives up additional energy when it condenses, and has more energy per kilogram than boiling water

when a vapor condenses

heat energy leaves the substance

when a vapor ondenses

heat energy leaves the substance

Food in a pressure cooker is cooked faster because of the

higher temperature

an adiabatic process

involves no net heat entering or leaving a system

your feet feel warmer on a rug than on a tile floor because the rug

is a better insulator than tile

when bringing water to a boil in the mountains, the time needed to reach the boiling point is

less than at sea level

double the absolute temperature of helium gas, and the molecules of helium, on average, speed up by

less than twice

convection can occur

only in liquids and gases

The silver coating on the glass surfaces of a Thermos bottle reduces energy that is transferred by

radiation

by what primary heat transfer mechanism does the sun warm the earth

radiation

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 best if the salt

raises the boiling point of water

when liquids change to a solid phase, they

release energy

when a gas is changed to a liquid phase, the gas

releases energy

metals are both good heat conductors and also god electrical conductors because of the

similarity between thermal and electrical conductive properties

A chunk of ice (T = -20°C) is added to a thermally insulated container of cold water (T = 0°C). What happens in the container?

some of the water freezes and the chunk of ice gets larger

what happens to water when heated from 0c degrees to 4c

the density increases is the water

a water-filled paper cup held in a flame will not catch fire. this is becuase

the paper cup cannot become appreciably hotter than the water it contains

what happens to a given mass of water when cooled between 4 and 0c

the water expands

We are warmed by condensation because water molecules in the air that strike our bodies

transfer some of their kinetic energy to us

geothermal heating or cooling

uses the ground as a heath source of heat sink

The cooling effect inside a refrigerator is produced by

vaporizing the refrigeration gas into a liquid

by blowing on a cup of hot coffee

we remove water vapor above the coffee so that further evaporation is enhanced

suppose you walk on red hot coals with bare feet. Providing bits of coal do not stick to your feet, it would be best if your feet are

wet