First law of thermodynamics problem

AI Thread Summary
The discussion revolves around solving a thermodynamics problem involving an ideal monoatomic gas in an insulated cylinder with a movable piston. The initial conditions are a pressure of 110 kPa and a temperature of 280 K, with the pressure increasing to 140 kPa. Participants highlight the challenge of using the equations due to the absence of volume and moles. The key point is that since the process is adiabatic (no heat exchange), the relationship between pressure and temperature must be considered, specifically noting that the equation P1/T1 = P2/T2 is only valid if volume remains constant. Understanding adiabatic processes is crucial for finding the final temperature in this scenario.
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Homework Statement


An ideal monoatomic gas is held in a perfectly insulated cylinder fitted with a movable piston. Initial pressure is 110kPa, initial temperature is 280K. By pushing on the piston the pressure increases to 140kPa. Find the final temperature.


Homework Equations



Q=nCdT (d means delta)

The Attempt at a Solution


I have thought of using the above eqn but moles is not given and i have thought of using PV=nRT but the volume isn't given either so i don't know how you can solve with two unknown variables. Please help
 
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you can use the equation P1/T1 = P2/T2 where P1 is initial pressure and T1 is initial Temperature and P2 is final pressure and T2 is final temperature.
 
XkitaX said:

Homework Statement


An ideal monoatomic gas is held in a perfectly insulated cylinder fitted with a movable piston. Initial pressure is 110kPa, initial temperature is 280K. By pushing on the piston the pressure increases to 140kPa. Find the final temperature.


Homework Equations



Q=nCdT (d means delta)

The Attempt at a Solution


I have thought of using the above eqn but moles is not given and i have thought of using PV=nRT but the volume isn't given either so i don't know how you can solve with two unknown variables. Please help
Welcome to physics forums.
Since the cylinder is insulated, there is no heat added (Q=0) and this is an adiabatic process. What does your textbook or class notes say about adiabatic processes and ideal gases? Hint: there is a relation between P and V involved.

Funkmaster W said:
you can use the equation P1/T1 = P2/T2 where P1 is initial pressure and T1 is initial Temperature and P2 is final pressure and T2 is final temperature.
That would be true if the volume were the same. But the volume changes in this problem.
 

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