Useful Summary of Thermodynamic Definitions
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 23858
- Joined: Thu Aug 04, 2011 1:53 pm
- Has upvoted: 1253 times
Useful Summary of Thermodynamic Definitions
In class today I forgot to mention this list I created to assist students.
Adiabatic (also called adiabatically isolated system)
An adiabatically isolated system has only adiabatic boundary sectors. Energy can be transferred as work, but transfers of matter and of energy as heat are prohibited. q = 0
Isothermal
An isothermal process is a change in a system where the temperature stays constant: ΔT = 0.
Isobaric
An isobaric process is a change in a system where the pressure stays constant: ΔP = 0.
Isochoric
An isochoric process is a change in a system where the volume stays constant: ΔV = 0.
Intensive property
An intensive property is a bulk property, meaning that it is a physical property of a system that does not depend on the system size or the amount of material in the system.
Note: The ratio of two extensive properties of the same object or system is an intensive property. For example, the ratio of an object's mass and volume, which are two extensive properties, is density, which is an intensive property.
State Function
A state function describes a physical property of the system and is independent of how the system arrived at its present condition.
Adiabatic (also called adiabatically isolated system)
An adiabatically isolated system has only adiabatic boundary sectors. Energy can be transferred as work, but transfers of matter and of energy as heat are prohibited. q = 0
Isothermal
An isothermal process is a change in a system where the temperature stays constant: ΔT = 0.
Isobaric
An isobaric process is a change in a system where the pressure stays constant: ΔP = 0.
Isochoric
An isochoric process is a change in a system where the volume stays constant: ΔV = 0.
Intensive property
An intensive property is a bulk property, meaning that it is a physical property of a system that does not depend on the system size or the amount of material in the system.
Note: The ratio of two extensive properties of the same object or system is an intensive property. For example, the ratio of an object's mass and volume, which are two extensive properties, is density, which is an intensive property.
State Function
A state function describes a physical property of the system and is independent of how the system arrived at its present condition.
-
- Posts: 59
- Joined: Fri Sep 25, 2015 3:00 am
-
- Posts: 5
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
So for adiabatic system, the energy as heat is different from the energy as work? Thanks!
-
- Posts: 14
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
This is going to be helpful when trying to keep track of the different vocab this quarter. Thanks!
Is this the main list for thermodynamics, or would it be recommended to extend the list on out own ?
Is this the main list for thermodynamics, or would it be recommended to extend the list on out own ?
-
- Posts: 22
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
Thank you! Just to clarify, are the only terms that are NOT state functions, work and heat?
-
- Posts: 13
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
can someone elaborate on state functions? i'm still kind of confused. are they dependent or dependent?
-
- Posts: 8
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
chrispolo15 wrote:can someone elaborate on state functions? i'm still kind of confused. are they dependent or dependent?
State functions are dependent on the state of the moment (temp/press/vol), but are independent of system "history"; I think it's more important to note that they are additive, like what we do with Hess's Law in enthalpy.
-
- Posts: 30
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
chrispolo15 wrote:can someone elaborate on state functions? i'm still kind of confused. are they dependent or dependent?
For a state property, you only need to know initial and final values. The pathway is not important.
Re: Useful Summary of Thermodynamic Definitions
jennymai96 wrote:So for adiabatic system, the energy as heat is different from the energy as work? Thanks!
energy as heat is always separate from energy as work. For Adiabatic systems, since there is no heat transfer, q=0 and Delta U = w
Re: Useful Summary of Thermodynamic Definitions
can someone elaborate more on the adiabetic system and its conditions?
-
- Posts: 4
- Joined: Fri Sep 20, 2013 3:00 am
Re: Useful Summary of Thermodynamic Definitions
Adiabatic as also defined in the textbook is, "not permitting or accompanied by the passage of energy as heat." This can be be categorized into two different processes, reversible and irreversible. Reversible is quasi-static where as the irreversible process is spontaneous since there is a big change in the external restriction. For reversible, quasi-static, it starts were gas pressure equals external pressure then there is a change externally where there is a slight decrease in the outside pressure. Therefore the gas expands just a bit before reaching equilibrium which occurs in a fast pace. This process is repeated until the desired pressure is reached. On the other hand if the outside pressure greatly decreased rapidly than the gas would expand until it reached equilibrium this process however will do so in a different manner than the reversible process.
-
- Posts: 45
- Joined: Fri Sep 25, 2015 3:00 am
Re: Useful Summary of Thermodynamic Definitions
This is great! Thank you for sharing these key terms in such a simple and concise way! These terms are essential to memorize for future quizzes and tests.
-
- Posts: 9
- Joined: Fri Sep 25, 2015 3:00 am
-
- Posts: 35
- Joined: Sat Jul 22, 2017 3:01 am
Re: Useful Summary of Thermodynamic Definitions
will we be discussing these different types of systems each in detail or should we just know the general conceptual idea behind them such as is provided here? thank you!
-
- Posts: 73
- Joined: Fri Sep 29, 2017 7:04 am
Re: Useful Summary of Thermodynamic Definitions
Would someone be able to briefly explain the difference between isobaric, isochoric, and isothermal? I have these definitions written down and I've read through the textbook, but I feel as though I've memorized the differences and don't fully grasp the concept. Thanks!
-
- Posts: 34
- Joined: Thu Jul 27, 2017 3:00 am
Re: Useful Summary of Thermodynamic Definitions
These 3 situations each have a different factor that remains the same. Isobaric refers to a system in which pressure remains constant, isochloric refers to a system in which volume remains constant, and isothermal refers to a system in which temperature remains constant. This means other factors are changing in order to change the entropy of a system. This is important because we use different equations in order to calculate entropy change based upon what the system's constants and variables are.
-
- Posts: 29
- Joined: Fri Sep 29, 2017 7:05 am
Re: Useful Summary of Thermodynamic Definitions
To clarify, intensive properties are ratios. For example, density would be an intensive property because it is mass/volume. Where mass and volume are both extensive properties.
Re: Useful Summary of Thermodynamic Definitions
Michelle Steinberg2J wrote:Would someone be able to briefly explain the difference between isobaric, isochoric, and isothermal? I have these definitions written down and I've read through the textbook, but I feel as though I've memorized the differences and don't fully grasp the concept. Thanks!
As Dr. Lavelle explained in his post,
Isobaric : constant pressure
Isochoric: constant volume
Isothermal: constant temperature
-
- Posts: 88
- Joined: Fri Sep 28, 2018 12:17 am
Re: Useful Summary of Thermodynamic Definitions
Just asking for clarification but for an Adiabatic isolated system as dr.lavelle stated that there can be exchange or more specificly loss of internal energy as work correct? So compared to an isolated system where there is no exchange of matter or energy because there is no surroundings therefore meaning that the internal energy is constant and doesn’t change for a Adiabatic isolated system the internal energy can DECREASE due to work correct? So between the two essentially the only difference would be that an Adiabatic system can lose internal energy as work because work is not within the limits of the Adiabatic boundaries correct? Verses the isolated system where there is absolutely no exchange of energy or matter because the system is “isolated” surroundings therefore meaning that there is no change at all in internal energy.
-
- Posts: 60
- Joined: Fri Sep 28, 2018 12:16 am
Re: Useful Summary of Thermodynamic Definitions
I am having trouble distinguishing the difference between a state function and an intensive property, they seem very similar to me.
-
- Posts: 46
- Joined: Fri Sep 28, 2018 12:16 am
Re: Useful Summary of Thermodynamic Definitions
will we need to identify processes as isobaric, isochoric, or isothermal?
-
- Posts: 29
- Joined: Fri Sep 28, 2018 12:21 am
Re: Useful Summary of Thermodynamic Definitions
I don't believe so, I think they tell us in the question so we use specific equations.Abby-Hile-1F wrote:will we need to identify processes as isobaric, isochoric, or isothermal?
-
- Posts: 76
- Joined: Wed Nov 21, 2018 12:18 am
-
- Posts: 50
- Joined: Fri Aug 30, 2019 12:16 am
Re: Useful Summary of Thermodynamic Definitions
Why does it matter if something is a state function or not? How does it affect the problem/question? I'm very confused.
-
- Posts: 131
- Joined: Fri Aug 02, 2019 12:15 am
Re: Useful Summary of Thermodynamic Definitions
Nathan Rothschild_2D wrote:Will we have to know these terms for the test?
I believe so because they can be used to describe something. For example yesterday during Lyndon workshop one of these words was used to describe the system and it was needed to solve the problem.
-
- Posts: 96
- Joined: Wed Nov 21, 2018 12:19 am
Re: Useful Summary of Thermodynamic Definitions
Thank you!
I think we will need to know these terms for the test in order to interpret problems
I think we will need to know these terms for the test in order to interpret problems
-
- Posts: 50
- Joined: Wed Nov 14, 2018 12:23 am
Re: Useful Summary of Thermodynamic Definitions
Michelle Steinberg2J wrote:Would someone be able to briefly explain the difference between isobaric, isochoric, and isothermal? I have these definitions written down and I've read through the textbook, but I feel as though I've memorized the differences and don't fully grasp the concept. Thanks!
The way I personally remember it:
isobaric: deltaP=0 (constant pressure)
isochoric: deltaV=0 (constant volume)
isothermal: deltaT=0 (constant temperature)
-
- Posts: 107
- Joined: Fri Aug 09, 2019 12:17 am
-
- Posts: 51
- Joined: Wed Nov 14, 2018 12:21 am
Re: Useful Summary of Thermodynamic Definitions
Thank you, this is such a helpful summary! I didn't realize that when you divide two extensive properties it ends up being an intensive, but now that makes sense.
-
- Posts: 106
- Joined: Sat Sep 14, 2019 12:17 am
Re: Useful Summary of Thermodynamic Definitions
Angela Wu-2H wrote:Why does it matter if something is a state function or not? How does it affect the problem/question? I'm very confused.
It matters because if you know it is a state function, you know that only the initial and final state matters. Since the path doesn't matter, you can subtract, add, multiply, and divide state functions.
In a path function, how you get the answer matters and you have to take each step in the path into consideration.
-
- Posts: 106
- Joined: Sat Sep 14, 2019 12:17 am
-
- Posts: 101
- Joined: Sat Sep 14, 2019 12:15 am
-
- Posts: 100
- Joined: Wed Sep 30, 2020 9:53 pm
- Been upvoted: 1 time
Re: Useful Summary of Thermodynamic Definitions
Thank you so much! I was having a hard time memorizing all of them, this really helps!
-
- Posts: 100
- Joined: Wed Sep 30, 2020 9:51 pm
-
- Posts: 103
- Joined: Wed Sep 30, 2020 9:51 pm
Re: Useful Summary of Thermodynamic Definitions
Melissa Kulon 2D wrote:Thank you! Just to clarify, are the only terms that are NOT state functions, work and heat?
Yup! Terms such as entropy, pressure, enthalpy, or color are state functions as they only depend on the current state they are in.
-
- Posts: 108
- Joined: Wed Sep 30, 2020 9:32 pm
-
- Posts: 101
- Joined: Wed Sep 30, 2020 9:36 pm
-
- Posts: 81
- Joined: Fri Aug 30, 2019 12:17 am
Re: Useful Summary of Thermodynamic Definitions
This is a very helpful summary, thank you for putting this together!
-
- Posts: 109
- Joined: Wed Sep 30, 2020 9:59 pm
-
- Posts: 103
- Joined: Wed Sep 30, 2020 9:59 pm
-
- Posts: 111
- Joined: Wed Sep 30, 2020 10:01 pm
Re: Useful Summary of Thermodynamic Definitions
This is super helpful!!! For adiabatic systems, doesn't delta q=0?
-
- Posts: 120
- Joined: Wed Sep 30, 2020 9:50 pm
Re: Useful Summary of Thermodynamic Definitions
This was super helpful, thank you so much for the summary!
-
- Posts: 102
- Joined: Fri Sep 24, 2021 5:33 am
-
- Posts: 34
- Joined: Mon Jan 09, 2023 10:13 am
Re: Useful Summary of Thermodynamic Definitions
Can someone please elaborate on “ The ratio of two extensive properties of the same object or system is an intensive property”? Is this statement true under any condition? Is there any other examples.
-
- Posts: 39
- Joined: Mon Jan 09, 2023 8:54 am
Re: Useful Summary of Thermodynamic Definitions
I have heard that adiabatic and isothermal processes are opposites of each other? Can anyone confirm if this is true and if so, why?
Re: Useful Summary of Thermodynamic Definitions
Thank you so much! just to clarify, state functions can be calculated like (final - initial), and is this connected to the integral ratio ( or in problems where you have to calculate ln(v2/v1) and equations like that?
-
- Posts: 23
- Joined: Mon Jan 09, 2023 8:24 am
Re: Useful Summary of Thermodynamic Definitions
Finding this after the midterm really is an L for me, but glad to have these definitions for future references.
-
- Posts: 34
- Joined: Mon Jan 09, 2023 8:38 am
Re: Useful Summary of Thermodynamic Definitions
It mentioned that an adiabatically isolated system has only adiabatic boundary sectors and energy can be transferred as work, but transfers of matter and of energy as heat are prohibited. Does that mean isolated systems can still have work done it or do work? There the change in internal energy of isolated systems would be = w.
-
- Posts: 31
- Joined: Mon Jan 09, 2023 2:33 am
Re: Useful Summary of Thermodynamic Definitions
Yes, this means adiabatic systems can do work and have work done to it and because the definition of adiabatic is that no heat is gained or lost than the change in internal energy would be equal to the work of the system. The internal energy change is also equal to the specific heat at constant volume times the change in temperature.
-
- Posts: 71
- Joined: Fri Sep 29, 2023 10:32 am
Return to “Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)”
Who is online
Users browsing this forum: No registered users and 5 guests