Chapter 24 Review

distinguish between the first and second laws of thermodynamics in terms of whether or not exceptions occur

1st-no exceptions 2nd-exceptions

in buildings that are electrically heated, turning the lights on

doesn't waste energy

if all the friction could be eliminated in a heat engine its efficiency would be 100%

false

When a volume of air is compressed and no heat enters or leaves, the air temperature will

increase

entropy measures

messiness

The ideal efficiency for a heat engine operating between temperatures of 2050K and 310K is

85%

adiabatic processes occur in

all of the above

It is possible to wholly convert a given amount of heat energy into mechanical energy

false

if the internal energy of a volume of air at 10C doubled its temperature would then be 20C

false

ceramic automobile engines that operate at higher temperature will be

more efficient

Systems that are left alone, tend to move toward a state of

more entropy

an absolute temperature of 110 K is the same as what C

-163 C

The lowest possible temperature in nature is

-273 degrees C

calculate the ideal efficiency of a power plant that runs between temperatures 400K and 150K

62.5%

the temperature of an object is raised by 70C. this is equivalent to what increase in its absolute temperature

70 C

an absolute temperature of 473 K is the same as what C

200 C

80 joules of heat is added to a system that performs 55 Joules of work. The internal energy change of the system is

25J

A volume of air has a temperature of 0 degrees Celsius. An equal volume of air that is twice as hot has a temperature of

273 Degrees C

at what temperature would the molecules of a gas have twice the average kinetic energy they have at 26C room temperature

325

there is a type of power plant known at OTEC that operates on the temperature difference between warm surface water and cool deep waters. What is the Carnot efficiency of such a plant if the surface water is 25C and the deep water is 4C

84%

cool a sample of air from zero on the Celsius scale to near zero on the absolute scale and the air loses

both A & B

when mechanical work is done on a system there can be an increase in its

both of the above

The first law of thermodynamics is a restatement of the

conservation of energy

if a volume of air is swept upward with no heat input or output its temperature

decreases

when work is done by a system and no heat is added to it the temperature of the system

decreases

air high in the atmosphere that plunges downward tends to cool

false

the greater the difference in temperature between the input reservoir and output reservoir for a heat engine, the

greater the efficiency

how does the second law of thermodynamics relate to the direction of heat flow

heat flows from hot to cold

pull a closed plastic bag of dry air quickly down from a high elevation and the bag of air will become

hotter

give two reasons why a tire pump becomes hotter when used to pump a tire

increase in internal energy/pressure and increase in external work

Suppose the temperature of the input reservoir in a heat engine doesn't change. As the sink temperature is lowered, the efficiency of the engine

increases

as a system becomes more disordered entropy

increases

you have a full jar of marbles. when you tip the jar over all of the marbles roll away. you would not expect the marbles to spontaneously order themselves back into the jar because

processes in which disorderly states tend toward orderly states are improbable and simply not observed

make up three examples to illustrate that natural systems tend to proceed toward greater entropy

run down house, campfire, free expansion of gas

entropy is closely related to the

second law of thermodynamics

two identical blocks of iron one at 10 degrees C and the other at 20 degrees C are put into contact. suppose the cooler block cools to 5 degrees C and the warmer block warms to 25 degrees C. this would violate the

second law of thermodynamics

what does it mean to say that energy becomes less organized when it transforms from one form to another

the quality of energy is lowered

Systems left alone tend to move to a state of greater entropy

true

efficiency in a heat engine is increased when there is a greater difference in input and output temperatures

true

it is possible to totally convert a given amount of mechanical energy into heat

true

when work is done by a system on something else the temperature of the system decreases

true

whenever heat is added to a system it transformed to an equal amount of some other form of energy

true

running a refrigerator with its door open in a hot room makes the room

warmer