Graph of several thermodynamic processes

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  • #1
tellmesomething
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Homework Statement
Graph these processes on a PV graph : Isothermal expansion from state A to B, isochoric pressure increment from B to C,
isothermal contraction from C to D, isobaric contraction from D to A.
Relevant Equations
!!!
I graphed it similar to this

IMG_20240314_204917.jpg


My query is say if the last process wasn't mentioned, I.e the process from A TO D, would the state D have the same pressure as state A then? In thermodynamics for a reversible system we say that if it undergoes a change in pressure volume the exact pressure and volume can he achieved when we reverse it, considering the temperature is constant. But here since we underwent an isochoric process from B to C and then reversed it, would it have ended at the same pressure of A if not for the last condition?
 
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  • #2
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
 
  • #3
BvU said:
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
Oh, sorry my question is typed wrong

[Post edited by a Mentor]
 
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  • #4
BvU said:
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
All fixed! Please give it another read i interchanged D & B by mistake
 
  • #5
BvU said:
Did you post the picture you intended to post?
I see the arrows going in the wrong direction, isochoric (at the same volume) and isobaric (at the same pressure) misinterpreted, etc...
Hi, if you have some free time, please consider clearing my doubt. Thankyou.
 
  • #6
Back from a short vacation, but I think we need more expertise. @Chestermiller ?
 
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  • #7
Fwiw: CD is an isothermic volume reduction down to a particular pressure. Whoever executes the cycle can choose that pressure; since DA is supposed to be isochoric, the choice of P at A makes sense.
 
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  • #8
BvU said:
Back from a short vacation, but I think we need more expertise. @Chestermiller ?
It seems to me the graph in post #1 is correct, except BC should be vertical.
 
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  • #9
BvU said:
Fwiw: CD is an isothermic volume reduction down to a particular pressure. Whoever executes the cycle can choose that pressure; since DA is supposed to be isochoric, the choice of P at A makes sense.
That was the doubt if pressure would have remained the same if the last isochoric condition wasnt there. Got it. thanks
 
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FAQ: Graph of several thermodynamic processes

What are the common types of thermodynamic processes represented in graphs?

The common types of thermodynamic processes represented in graphs include isothermal (constant temperature), isobaric (constant pressure), isochoric (constant volume), and adiabatic (no heat exchange). Each process has a distinct path on a Pressure-Volume (P-V) or Temperature-Entropy (T-S) diagram.

How can you identify an isothermal process on a P-V diagram?

An isothermal process on a P-V diagram appears as a hyperbolic curve. This is because, for an ideal gas, the product of pressure and volume (P*V) remains constant during an isothermal process, following Boyle's Law.

What distinguishes an adiabatic process from an isothermal process on a P-V diagram?

An adiabatic process on a P-V diagram is steeper than an isothermal process. In an adiabatic process, the pressure and volume change without heat exchange, following the relation P*V^γ = constant, where γ (gamma) is the heat capacity ratio (Cp/Cv). In contrast, an isothermal process follows P*V = constant.

How do isobaric and isochoric processes appear on a P-V diagram?

On a P-V diagram, an isobaric process appears as a horizontal line, indicating constant pressure while volume changes. An isochoric process appears as a vertical line, indicating constant volume while pressure changes.

What is the significance of the area under the curve in a thermodynamic process graph?

The area under the curve in a P-V diagram represents the work done by or on the system during the process. For example, in an isobaric process, the work done is equal to the pressure multiplied by the change in volume. In other thermodynamic processes, the area under the curve can be calculated to determine the work done.

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