Thermodynamics Practice Problems 2012-05-07

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ThermodynamicsAP Physics B Name____________________________________

Multiple Choice Questions

1. What is the name of the following statement: When two systems are inthermal equilibrium with a third system, then they are in thermal equilibriumwith each other!

"#$ %irst &aw of 'hermodynamics

"($ )econd &aw of 'hermodynamics

"C$ Mechanical equi*alent of heat

"+$ eroth &aw of 'hermodynamics

"-$ 'hermal epansion of solids

/. #n aluminum plate has a circular hole. 0f the temperature of the plateincreases, what happens to the sie of the hole!

"#$ 0ncreases

"($ +ecreases

"C$ )tays the same

"+$ 0ncreases the top half of the hole

"-$ More information is required


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2. # bimetal plate consists of two materials of di3erent coe4cients of thermalepansion. 'he coe4cient of thermal epansion of the top part of the plate isless than the bottom part. 0f the temperature of the entire plate increases,what happens to the plate!

"#$ -pends

"($ Contracts

"C$ )tays the same

"+$ (ends down

"-$ (ends up

5. Which of the following temperature scales doesn6t ha*e negati*e numbers!

"#$ Celsius

"($ 7el*in

"C$ 8eaumur

"+$ %ahrenheit

"-$ 9alileo

. Which of two temperature change are equi*alent!

"#$ 1 7 ; 1 %

"($ 1 % ; 1 C

"C$ 1 8e ; 1 %

"+$ 1 7 ; 1 C

"-$ 1 8e ; 1 7


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'2

"C$ '1> '/> '2

"+$ '1= '/; '2

"-$ '1; '/= '2

?. # container @lled with a sample of an ideal gas at the pressure of 1. atm.'he gas is compressed isothermally to oneAfourth of its original *olume. What

is the new pressure of the gas!"#$ / atm "($ 2 atm "C$ 5 atm "+$ atm "-$ 2

"C$ 1> /> 2

"+$ 1; /= 2

"-$ 1= /; 2

D. 'he temperature of an ideal gas increases from /E FC to 5E FC while thepressure stays the same. What happens to the *olume of the gas!

"#$ 0t doubles

"($ 0t quadruples

"C$ 0t is cut to oneAhalf

"+$ 0t is cut to oneAfourth


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"-$ it slightly increases

1E.'he state of an ideal gas was changed three times in a way that the *olumestays the same. 'he graph represents three isobaric lines. Which of thefollowing is true about the *olume of the gas!

"#$ G1=G/=G2

"($ G1= G/> G2

"C$ G1> G/> G2

"+$ G1; G/= G2

"-$ G1= G/; G2

11.# container with rigid walls @lled with a sample of ideal gas. 'he absolutetemperature of the gas is doubled. What happens to the pressure of the gas!

"#$ +oubles

"($ Quadruples

"C$ 'riples

"+$ +ecreased to oneAhalf

"-$ +ecreased to oneAfourth

1/.'he absolute temperature of an ideal diatomic gas is quadrupled. Whathappens to the a*erage speed of molecules!


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"#$ Quadruples

"($ +oubles

"C$ 'riples

"+$ 0ncreases by a factor of 1.51

"-$ )tays the same

12.'wo containers are @lled with diatomic hydrogen gas and diatomic oygengas. 'he gases ha*e the same temperature. Compare the a*erage speed ofhydrogen molecules to the a*erage speed of oygen molecules.

"#$ 1H1 E, Q ; E "C$ ' ; E, Q ; E "+$ ' = E,Q > E "-$ ' ; E, Q > E

1.'he state of an ideal gas is changed in a closed path 1R/R2R5R1. Which ofthe following is true about worI done on the gas!

WorI 1R/ WorI /R2 WorI 2R5 WorI 5R1

"#$ W = E W ; E W > E W ; E

"($ W > E W ; E W ; E W = E

"C$ W > E W ; E W = E W ; E


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"+$ W ; E W = E W ; E W > E

"-$ W ; E W > E W ; E W = E

1


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1?.#n ideal gas is taIen through a closed path 1R/R2R5R1. What is the networI done by the gas!

"#$


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1D.# sample of an ideal gas taIen through a closed cycle is presented by the AGdiagram. 'he process 1A/ is perfectly isothermal. Which of the following istrue about the change in internal energy and worI done by the gas during theprocess 1A/!

"#$ L ; E W by the gas= E

"($ L = E W by the gas ; E

"C$ L > E W by the gas > E

"+$ L ; E W by the gas; E

"-$ L ; E W by the gas > E


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/E.# sample of an ideal gas is taIen through a closed cycle presented by AGdiagram. 'he process 1A/ is perfectly isothermal. Which of the following is

true about the change in internal energy and heat added to the gas duringthe process 2A1!

"#$ L ; E Q = E

"($ L = E Q= E

"C$ L > E Q> E

"+$ L ; E Q ; E

"-$ L ; E Q> E

/1.'he state of an ideal gas is changed in four di3erent steps #R(, (RC, CR+,+R#. 'he gas is mo*ed from the state C to the state + isothermally. +uringwhich process is no worI done by the gas!

"#$ #R( "($ (RC "C$ CR+ "+$ +R# "-$ More

information is required


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//.#n ideal gas undergoes a cyclic process presented by the AG diagram. Whichof the following points has the highest temperature!

"#$ # "($ ( "C$ C "+$ + "-$ -


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/2.#n ideal gas can be taIen from point 7 to point J in three di3erent paths:7R&RJ, 7RJ, 7RMRJ. Which of the following is a true statement!

"#$ 'he same worI is done during each process

"($ 'he same amount of heat is added to the gas during each process

"C$ 'he same change in internal energy during each process

"+$ 'here is no worI done in the process 7RJ

"-$ 'here is no change in internal energy during the process 7R&RJ

/5.#n ideal heat engine operates between two temperatures


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%ree 8esponse problems

1. / moles of a monatomic ideal gas is placed under a piston in acylindrical container. 'he piston can mo*e freely up and down withoutfriction and its diameter is /E cm. # E Ig weight is placed on the topof the piston. 'he initial temperature of the gas is E FC.

a. Calculate the absolute pressure in the container.

b. Calculate the *olume of the gas.

'he gas is heated to a temperature of a 1EE FC at the constant

pressure.

c. Calculate the new *olume of the gas.

d. Calculate the amount of worI done by the gas duringits epansion.

e. Calculate the change in internal energy of the gas.

f. Calculate the amount of heat added to the gas.


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1. Tne mole of a monatomic ideal gas is taIen from state # to state (isobarically.

a. Uow much worI is done on the gas duringthe process #R(!

b. What is the change in internal energy L# PL(!

c. 0s heat added or remo*ed from the gasduring the process #R(!

d. Uow much heat is added or remo*ed fromthe gas!

'he state of the gas is changed from (RC where the pressuredrops to 2EE a without

any change in *olume and after the gas is compressed to point #

isothermally.e. Tn the diagram below show the complete

cycle #R(RCR#.


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1. #n ideal gas can be taIen from state a to state c in three di3erentpaths: aRbRc, aRdRc, and cur*ed path aRc. 'he pressure of the idealgas at point a is three times the pressure at point d. Lse the followinginformation to answer all questions:

Q aRc; A1/E "cur*ed path$


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W aRc; ? "cur*ed path$

W aRdRc; D

LaP Ld ; /E

0n the gi*en information abo*e we assume that worI is done on thegas.

a. %ind the change in internal energy LaPLc.

b. %ind the heat added to the gas in the process aRdRc.

c. %ind the worI done on the gas in the process aRbRc.

d. %ind the heat added to the gas in the process aRbRc.


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1. Tne mole of an ideal gas is taIen through a closed cycle #R(RCR#.

Lse the information from the graph to answer the following questions:

a. %ind the temperature at point #.

b. 0s the net worI done by the gas positi*e or negati*e!-plain.

c. Uow much worI is done by the gas!

d. 0s heat added to the gas or remo*ed from the gas forthe entire cycle! -plain.

e. Uow much heat is added to the gas!

f. What is the change in internal energy for the entire cycle!


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Answers:

Multiple Choice

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2. -

5. (

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Thermodynamics Practice Problems 2012-05-07