Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

Published by Pearson
ISBN 10: 0321740904
ISBN 13: 978-0-32174-090-8

Chapter 17 - Work, Heat, and the First Law of Thermodynamics - Exercises and Problems - Page 500: 69

Answer

See the detailed answer below.

Work Step by Step

First of all, we need to find the number of moles of this gas $$n=\dfrac{m}{M_{N_2}}=\dfrac{m}{2M_N}$$ Plugging the known; $$n=\dfrac{14\;\rm g}{\rm 2(14)\;g/mol}=\bf 0.5\;\rm mol $$ Noting that STP means standard temperature and pressure at which the temperature is 0$^\circ$C and the pressure is 1 atm. So we can find the initial volume by applying the ideal gas law; $$PV=nRT$$ Hence, $$V1=\dfrac{nRT_1}{P_1}=\dfrac{(0.5)(8.31)(0+273)}{(1.013×10^5)}$$ $$V_1=\bf 11.2\times 10^{-3}\;\rm m^3$$ ______________________________________________________________ a) For an isochoric process, the final temperature is given by $$\dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}$$ Hence, $$T_2=\dfrac{P_2T_1}{P_1}$$ Plugging the known; $$T_2=\dfrac{(20)(0+273)}{1}$$ $$T_2=\color{red}{\bf 5460}\;\rm K$$ ______________________________________________________________ b) For an isochoric process, the work done on the gas is zero since the volume is constant. $$W=\color{red}{\bf 0}\;\rm J$$ ______________________________________________________________ c) We know that the change in thermal energy of the gas during any process is given by $$\Delta E_{th}=Q+W=Q+0$$ Hence, $$Q=\Delta E_{th}=nC_{\rm v}(T_2-T_1)$$ Plugging the known; $$Q= (0.5)(20.8)(5460−273)$$ $$Q=\color{red}{\bf 5.39\times 10^4}\;\rm J$$ ______________________________________________________________ d) For an isochoric process, $$\dfrac{P_2}{P_1}=\dfrac{T_2}{T_1}=\dfrac{5460}{273}=\bf 20 $$ This means that $P_2=20P_1$ which means that $P_2$ is the maximum pressure. $$\dfrac{P_{\rm max}}{P_{\rm min}}= \color{red}{\bf 20 }$$ ______________________________________________________________ e) To draw this process, we need to know the initial and final points. The initial point is: $(V_1,P_1)=\rm ( 11,200\;\rm cm^3,1\;atm)$ And the final point is: $(V_2,P_2)=\rm ( 11,200\;\rm cm^3,20\;atm)$ ----
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.