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ID: 1992302 • Letter: H
Question
number 27
2007-5 (KT and TD)The figure above shows a 0.20 m diameter cylinder fitted with a frictionless piston, initially fixed in place. The cylinder contains 2.0 moles of nitrogen gas at an absolute pressure of 4.0x105 Pa.Nitrogen gas has a molar mass of 28 g mole and it behaves as an ideal gas.a. Calculate the force that the nitrogen gas exerts on the piston.b. Calculate the volume of the gas if the temperature of the gas is 300 K.c. In a certain process, the piston is allowed to move, and the gas expands at constant pressure and pushes the piston out 0.15 m. Calculate how much work is done by the gas.d. Which of the following is true of the heat energy transferred to or from the gas, if any, in the process in part c?_____ Heat is transferred to the gas._____ Heat is transferred from the gas._____ No heat is transferred in the process.Justify your answer.
i am not sure why but all my answers are off by a degree (example, 1000 instead of 100)
Explanation / Answer
a) F=P*A=4E5*3.14*.2^2=50240 N b) use PV =nRT, 4E5*V=28*8.31*300 so V=0.175 m^3 c) W=P dV= P A h= 4E5*3.14*.2^2*0.15=7536 d) so we know dU=Q-W we know W is positive and since P went up T went up so dU>0 Q=dU+W so that is positive that means heat is transferred to the gas.
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