First law of thermodynamics problem

In summary, an ideal monoatomic gas in a perfectly insulated cylinder with an initial pressure of 110kPa and temperature of 280K is subjected to a pressure increase to 140kPa by pushing on a movable piston. To find the final temperature, the adiabatic process and relation between pressure and volume must be considered, as well as the equation P1/T1 = P2/T2 where P1 and T1 are initial values and P2 and T2 are final. However, since the volume changes in this problem, another approach is needed to solve for the final temperature.
  • #1
XkitaX
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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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  • #2
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.
 
  • #3
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.
 

FAQ: First law of thermodynamics problem

What is the first law of thermodynamics?

The first law of thermodynamics is a fundamental principle in physics that states that energy cannot be created or destroyed, only transformed from one form to another. This law is also known as the law of conservation of energy.

How does the first law of thermodynamics apply to a problem?

The first law of thermodynamics can be used to solve problems involving the transfer and transformation of heat and work in a system. It can help determine the change in internal energy, heat transfer, and work done in a thermodynamic process.

What is the formula for the first law of thermodynamics?

The first law of thermodynamics can be expressed as: ΔU = Q - W, where ΔU is the change in internal energy of the system, Q is the heat added to the system, and W is the work done on the system.

How is the first law of thermodynamics related to the conservation of energy?

The first law of thermodynamics is closely related to the principle of conservation of energy. It states that the total energy of a closed system remains constant, and any change in energy must be accounted for by heat transfer or work done.

What are some real-life applications of the first law of thermodynamics?

The first law of thermodynamics has numerous applications in everyday life, such as in the functioning of car engines, refrigerators, and air conditioners. It also applies to energy conservation and the study of energy efficiency in various processes.

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