2
Thermodynamics Review Unit 11 Physics questions with verified || || || || || || || ||
detailed answers ||
0th Law of Thermodynamics - ✔✔If two systems are in thermal equilibrium with a third
|| || || || || || || || || || || || || || ||
system, then they're in thermal equilibrium with each other.
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1st Law of Thermodynamics - ✔✔If heat is transferred to or from a system then the system
|| || || || || || || || || || || || || || || || ||
gains/loses an amount of energy equal to heat transferred.
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2nd Law of Thermodynamics - ✔✔Heat flows spontaneously from high to low
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temperatures.
3rd Law of Thermodynamics - ✔✔It is not possible to reach absolute zero.
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Adiabatic Process - ✔✔Very rapid process where no heat is allowed to enter or leave the
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system.
Isothermal Process - ✔✔Process that occurs at a constant temperature.
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Isobaric Process - ✔✔Process that occurs at a constant pressure.
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Isovolumetric Process - ✔✔Process that occurs at a constant volume. || || || || || || || || ||
Entropy - ✔✔Measure of disorder in a system.
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What is the purpose of the 0th law of Thermodynamics? - ✔✔It defines temperature in
|| || || || || || || || || || || || || || ||
terms of heat flow.
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, 2
What is the 1st law of thermodynamics a restatement of? - ✔✔Restatement of COE
|| || || || || || || || || || || || || ||
(Conservation of Energy). || ||
What are three different ways to state the 2nd law of thermodynamics? How are these three
|| || || || || || || || || || || || || || || ||
statements related? - ✔✔- entropy || || || ||
- always increasing
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- not possible to have a 100% heat engine
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What happens to the efficiency of a heat engine when the temperature of the exhaust
|| || || || || || || || || || || || || || ||
reservoir is lowered? - ✔✔As temperature of exhaust reservoir decreases, the efficiency of
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the engine increases. As exhaust reservoir temperature approaches 0K (absolute zero), the
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engine approaches 100% efficiency.
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Which has higher entropy, ice or steam. Why? - ✔✔Steam, because the molecules have
|| || || || || || || || || || || || || ||
more freedom to move around its surroundings, causing more random disorder than ice.
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Explain how a power plant works. - ✔✔Water from the lake goes into the power plant, the
|| || || || || || || || || || || || || || || || ||
water boils in the HTR then turns into steam and goes through the turbine then it
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condenses and goes through the LTR and goes back into the lake.
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Explain how a four stroke engine works. - ✔✔INTAKE--> valve is open/piston moves
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down/air fuel moves into cylinder. || || || ||
COMPRESSION--> both valves are closed/piston moves up/air fuel is compressed and || || || || || || || || || || ||
increases in temperature and pressure. || || || ||
POWER--> both valves are closed/piston is moving down/air fuel mixture is ignited at
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beginning of power strike by spark plug/expansion forces the piston down.
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EXHAUST--> exhaust valve is open/piston is moving up/burned air fuel mixture leaves the
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chamber.
Thermodynamics Review Unit 11 Physics questions with verified || || || || || || || ||
detailed answers ||
0th Law of Thermodynamics - ✔✔If two systems are in thermal equilibrium with a third
|| || || || || || || || || || || || || || ||
system, then they're in thermal equilibrium with each other.
|| || || || || || || ||
1st Law of Thermodynamics - ✔✔If heat is transferred to or from a system then the system
|| || || || || || || || || || || || || || || || ||
gains/loses an amount of energy equal to heat transferred.
|| || || || || || || ||
2nd Law of Thermodynamics - ✔✔Heat flows spontaneously from high to low
|| || || || || || || || || || || ||
temperatures.
3rd Law of Thermodynamics - ✔✔It is not possible to reach absolute zero.
|| || || || || || || || || || || ||
Adiabatic Process - ✔✔Very rapid process where no heat is allowed to enter or leave the
|| || || || || || || || || || || || || || || ||
system.
Isothermal Process - ✔✔Process that occurs at a constant temperature.
|| || || || || || || || ||
Isobaric Process - ✔✔Process that occurs at a constant pressure.
|| || || || || || || || ||
Isovolumetric Process - ✔✔Process that occurs at a constant volume. || || || || || || || || ||
Entropy - ✔✔Measure of disorder in a system.
|| || || || || || ||
What is the purpose of the 0th law of Thermodynamics? - ✔✔It defines temperature in
|| || || || || || || || || || || || || || ||
terms of heat flow.
|| || ||
, 2
What is the 1st law of thermodynamics a restatement of? - ✔✔Restatement of COE
|| || || || || || || || || || || || || ||
(Conservation of Energy). || ||
What are three different ways to state the 2nd law of thermodynamics? How are these three
|| || || || || || || || || || || || || || || ||
statements related? - ✔✔- entropy || || || ||
- always increasing
|| ||
- not possible to have a 100% heat engine
|| || || || || || || ||
What happens to the efficiency of a heat engine when the temperature of the exhaust
|| || || || || || || || || || || || || || ||
reservoir is lowered? - ✔✔As temperature of exhaust reservoir decreases, the efficiency of
|| || || || || || || || || || || || ||
the engine increases. As exhaust reservoir temperature approaches 0K (absolute zero), the
|| || || || || || || || || || || ||
engine approaches 100% efficiency.
|| || ||
Which has higher entropy, ice or steam. Why? - ✔✔Steam, because the molecules have
|| || || || || || || || || || || || || ||
more freedom to move around its surroundings, causing more random disorder than ice.
|| || || || || || || || || || || ||
Explain how a power plant works. - ✔✔Water from the lake goes into the power plant, the
|| || || || || || || || || || || || || || || || ||
water boils in the HTR then turns into steam and goes through the turbine then it
|| || || || || || || || || || || || || || || ||
condenses and goes through the LTR and goes back into the lake.
|| || || || || || || || || || ||
Explain how a four stroke engine works. - ✔✔INTAKE--> valve is open/piston moves
|| || || || || || || || || || || || ||
down/air fuel moves into cylinder. || || || ||
COMPRESSION--> both valves are closed/piston moves up/air fuel is compressed and || || || || || || || || || || ||
increases in temperature and pressure. || || || ||
POWER--> both valves are closed/piston is moving down/air fuel mixture is ignited at
|| || || || || || || || || || || || ||
beginning of power strike by spark plug/expansion forces the piston down.
|| || || || || || || || || ||
EXHAUST--> exhaust valve is open/piston is moving up/burned air fuel mixture leaves the
|| || || || || || || || || || || || ||
chamber.
