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A gas confined within a piston-cylinder assembly undergoes a process where it expands at constant pressure of 2 \mathrm{~atm} from a volume of \mathrm{0.02 \mathrm{~m}^3\: to\: 0.04 \mathrm{~m}^3} During this process, 1500 \mathrm{~J} of heat is added to the gas. Calculate the work done by the gas and its change in internal energy.
 

Option: 1

20265,-18765 \mathrm{~J}

 


Option: 2

15469 \mathrm{~J}
 


Option: 3

5452 \mathrm{~J}
 


Option: 4

21542 \mathrm{~J}


Answers (1)

best_answer

Given data:

Pressure,\mathrm{ P=2 \mathrm{~atm}}

Initial volume, \mathrm{V_1=0.02 \mathrm{~m}^3}

Final volume, \mathrm{V_2=0.04 \mathrm{~m}^3}

Heat added, \mathrm{Q=1500 \mathrm{~J}}

First, calculate the work done

\mathrm{ W=P \cdot \Delta V }

\mathrm{ W=2 \mathrm{~atm} \cdot\left(0.04 \mathrm{~m}^3-0.02 \mathrm{~m}^3\right) \cdot 101325 \mathrm{~Pa} / \mathrm{atm} }

\mathrm{ W=20265 \mathrm{~J} }

Now, use the First Law of Thermodynamics to calculate the change in internal energy:

\mathrm{\Delta U =Q-W }

\mathrm{\Delta U =1500 \mathrm{~J}-20265 \mathrm{~J} }

\mathrm{\Delta U =-18765 \mathrm{~J} }

Hence oprion 1 is correct.




 

Posted by

manish painkra

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