Final exam
The lowest temperature possible in nature is
-273 degrees C
Entropy is closely related to the
2nd law of thermodynamics
Two identical blocks of iron, one at 10 degrees C and the other at 20 degrees C, are put in contact. Suppose the cooler block cools to 5 degrees C and the warmer block warms to 25 degrees C. This would violate the
2nd law of thermodynamics
One hundred joules of heat is added to a system that performs 60 joules of work. The internal energy change of the system is
40 J
The ideal efficiency for a heat engine operating between the temperatures of 227 degrees C and 27 degrees C is
40%
The ideal efficiency for a heat engine operating between temperatures of 2050 K and 310 K is
85%
Which of these units of temperature is larger?
Both are the same
Whenever heat is added to a system, it transforms to an equal amount of some other form of energy.
True
Why do diesel engines have no use for spark plugs?
Very high compression already.
An adiabatic process is characterized by the absence of
heat exchange
If the internal energy of a volume of air at 10ºC is doubled, its temperature will then be 20ºC.
False
When mechanical work is done on a system, there can be an increase in
both temperature and internal energy
Blow on your hand with your open mouth and you feel the warmth of your breath. Pucker your lips so your breath expands as you blow and your breath is
cooler
When a volume of air expands against the environment and no heat enters or leaves, the air temperature will
decrease
If a blob of air is swept upward, with no heat input or output, its temperature
decreases
When a system does work and no heat is added to the system, its temperature
decreases
The greater the difference in temperature between the input reservoir and the output reservoir for a heat engine, the
greater efficiency
To wholly convert a given amount of heat energy into mechanical energy is
impossible regardless of the technique used
Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will
increase
As a system becomes more disordered, entropy
increases
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
Of the choices given , what are the correct actions of a 4 stroke engine in order.
intake, compression, ignition, powerstroke, exhaust
Suppose you put a closed, sealed can of air on a hot stove burner. The contained air will undergo an increase in
internal energy, temperature and pressure
The first law of thermodynamics is a restatement of the
law of conservation of energy
Systems that are left alone, tend to move toward a state of
more entropy
During an adiabatic compression of an ideal gas
no heat is supplied to or removed from the gas
You have a jar full 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
Chinook winds tend to
warm an environment
A temperature inversion occurs when the upper layers of air are
warmer than the lower regions of air
