Ch. 23+24 Physics test
Freezing occurs when matter changes from a
liquid to a solid.
Calculate the ideal efficiency of a power plant that runs between temperatures 600 K and 400 K.
(600-400)/600
Ideal Efficiency
(T hot - T cold)/T hot
At what temperature would the molecules of a gas have twice the average kinetic energy they have at a 20°C room temperature?
20+273= 293
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.
An ice skater skates on a thin film of water between the blades and the ice.
True
If 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 about 273 degrees C.
True
If air pressure above water is removed, the water will boil and the resulting cooling can turn the water to ice.
True
It is possible to totally convert a given amount of mechanical energy into heat.
True
The process of boiling actually cools the water.
True
The greater the difference in temperature between the input reservoir and output reservoir for a heat engine, the
greater the efficiency.
When water freezes, it
gives off energy
At high altitudes, the boiling point of water
is lower.
Increased air pressure on the surface of hot water tends to
prevent boiling
As a system becomes more disordered, entropy decreases.
False
It is possible to wholly convert a given amount of heat energy into mechanical energy.
False
The lowest temperature possible in nature is 4 K.
False
When ice changes to water at 0 degrees Celsius, energy is released.
False
When steam changes to water at 100 degrees Celsius, energy is released.
False
Clouds form when warm air
chills. expands. rises
The first law of thermodynamics is a restatement of the
conservation of energy.
When a volume of air expands against the environment and no heat enters or leaves, the air temperature will
decrease.
The molecules in a room-temperature glass of water jostle around at
great variety of speeds.
When a volume of air compresses and no heat enters or leaves, the air temperature will
increase.
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. pressure.
Evaporation is a cooling process and condensation is
the more energetic molecules escape the liquid. the temperature of the remaining liquid decreases.