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Questions tagged [thermodynamics]

Covers the study of (mostly homogeneous) macroscopic systems from a heat/energy/entropy point of view. Consider also using tag: [statistical-mechanics].

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What free thermodynamic software is available for Mac?

I have used CoolProp for use in excel for thermodynamic data on windows computers but since that isn't available on Mac I was wondering if there are any similar packages freely available?
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van der Waals equation of state plot limitations

When I plot the van der Waals equation of state in terms of Pressure (bar) versus density (mol/L) for propane at 400 K, $$P=\frac{RT}{\big(V_m-b\big)}-\frac{a}{V_m^2}$$ and so $$P=\frac{RT}{\big(...
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How will the laws of thermodynamics change due to the use of complex velocity? [on hold]

The square of complex speed can be negative $$\sum_k (Re V_k\pm i Im V_k)^2=\sum_k[(Re V_k)^2-(Im V_k)^2 \pm 2 i Re V_k Im V_k]\approx \sum_k[(Re V_k)^2-(Im V_k)^2]. $$ At the same time, along with ...
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1answer
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Why was it cold during inflation?

During inflation, the universe is expected to be "cold", i.e. there is no hot thermal plasma, just the inflaton field. It warms back up at the end of inflation, when the inflaton field is postulated ...
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Bose Condensation; interacting vs. non-interacting

I have some problems unifying, the two way I learned how a Bose condensate appears. The main problem is that the observables seem to be quite different. In statistical physics lecture one starts with ...
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Heat engine carnot cycle [on hold]

Two Carnot engines e first one, A and A receives B are operated heat from in a source at T1-800Kand rejects to a sink at T2K. The second engine B receives heat rejected by the first engine and rejects ...
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Does a quantum phase transition (QPT) necessarily require $T=0$ or $T\to 0$? Can QPT occur at finite but fixed $T$ sitting as a spectator?

Consider a phase transition occurring at a finite but fixed temperature e.g. transition of a ferromagnetic state with all spins up to another sibling state with all spins down by reversing the ...
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Polymer statistics [on hold]

I have polymer statistics homework that i need help on: 1) Determine the force-extension behavior of the freely jointed chain (FJC) and the worm-like chain (WLC) models of polymers in the limit of ...
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29 views

Relationship between physical and information entropy [duplicate]

This question is inspired by the following example given in Barnett's book on quantum information: (PDF here, starting at the bottom of page 5) I am not a physicist, but I'll accept that the ...
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25 views

How do all chemical reactions result in a product whose potential is less than the reactants if all reactions are not exothermic?

We are told by our chemistry teacher that all chemical reactions take place as reactants (that have bigger potential) change into products (that have smaller potential) hence unstable substances ...
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What is the criteria of trapped ideal gas to form Bose-Einstein condensate (BEC)?

If we have ideal gas of bosons in a trapped harmonic potential, is the only necessary thing for BEC is a temperature less than the transition temperature? Or is there any other things we should keep ...
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partition function of distinguishable/indistinguishable particle where any number/at most one of them can occupy a state

Say we have a system with 2 particles with energy levels $E_1=0,E_2=E,E_3=2E,E_4=2E$. I want to figure out the partition function of the system depending on whether i) the particles are ...
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Is there a difference between false (metastable) and local equilibria?

Or is it permissible to use the terms interchangeably? If there is a difference, what is it?
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1answer
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Potts model equivalent to Heisenberg model

The mean-field equations for the three-state Potts model $$ \mathcal{H}=-J\sum_{\langle ij \rangle}\delta_{\sigma_i\sigma_j}\:,\qquad\sigma_i=1,\,2,\,3 $$ is equivalent to $$ \mathcal{H}=-J\sum_{\...
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Thermodynamics Heat Question [on hold]

Suppose 1300 kJ of heat is added to 1.1 kg of ice at -2.0 degrees Celsius. Compute the final Temperature. I am really confused on how to solve this. What do I do the compute the final temperature?
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Doubt in thermodynamics pressure volume work done

Why work done in irreversible process is not calculated as -$\int p_{internal} dV$ ?
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1answer
39 views

Isothermal expansion of real gas - pressure change

I have been studying isothermal expansion process, the heat change particulary for a real gas. On the internet is many solved problems about this, but it's always about changing volume from $v_i$ to $...
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3answers
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Why do energy transfers always result some heat loss?

explain that energy transfers and transformations in mechanical systems always result in some heat loss to the environment. Like why is it necessary for a heat loss?
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Is it possible to “override” the electromagnetic field from an MRI scan? And how do you do it? [on hold]

I know electro conductors lose their charge if you heat them. Is there a better way to negate it and how?
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2answers
40 views

Basic First Law of Thermodynamics Question [on hold]

$2$ kg of water is heated by stirring. If this process raises the temperature of water from $15^{\circ}$ C to $25^{\circ}$ C, how much work, in joules, was done to the water by the stirring? I ...
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23 views

Determining pressure as a function of time for water filled balloon

Looking to determine pressure as a function of time for a water filled "balloon" at extremely high pressures (~90MPa) with a fixed flow rate out. This is to determine the time it takes to hit a ...
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49 views

Calculation of free energy for Bloch electrons

The question is based on Eq. 6-9 in this paper https://arxiv.org/abs/0704.3824. Basically the free energy is defined as $ K({\bf r}) =\sum_{n{\bf k}} f_{n{\bf k}}\text{Re}\left\{\psi_{n{\bf k}}^*({...
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Total heat loss from Human body [duplicate]

I want to calculate total heat loss from human body.Please tell me how I will determine total heat loss from human body?
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1answer
34 views

Relations derived from ist law of thermodynamics

In the 5th point given in the image, it is mentioned that this relation is applicable for both reversible and irreversible processes, since the parameters involved are state functions i.e independent ...
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3answers
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Why do gas expand when heated?

So as a volume of gas is heated, the addition of energy increase the particles' kinetic energy. This only means that they are now moving faster right? I cannot relate this increase of kinetic energy ...
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2answers
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how can internal energy do work?

how can internal energy do work? As far as i know, internal energy is the sum of KE and PE. But how can this, in turn, do work? It would be great if you can give me some scenarios. Thank you.
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How does the Diameter $d$ get squared in this ideal gas solution? [on hold]

If $n$ moles of an ideal gas at temperature 4K can be pumped through a tube of diameter $d$, what must be the diameter of the tube to pump the same nuber of moles of gas at the temperature 300K? ...
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Is there any change in temperature due to special relativity? [duplicate]

Say I am travelling in a spaceship very close to the speed of light. Would there be any change in temperature in the spaceship relative to outside the spaceship? Please explain in detail.
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2answers
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Is it possible to have a planet entirely made out of liquid water?

Earth is mostly covered in oceans, but they only go a few kilometres deep. It's obviously not possible to have a planet the size of the earth to be made entirely out of water, because of the kind of ...
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Energy loss of gas due to Collisions [on hold]

A large number of identical elastic balls are moving randomly in a fixed vertical cylinder under a piston that is at height H above the bottom of container. The container is kept in a gravity free ...
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2answers
51 views

Compression of gas [on hold]

What happens when a gas kept in a metallic container is suddenly compressed via a piston and left for some time? Does the pressure increase or decrease?
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1answer
37 views

How does thermal energy in a system do mechanical work? [on hold]

Explain that a system with thermal energy has the capacity to do mechanical work. Also, in addition to this what are the differences between work and mechanical work?
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1answer
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How can one the find normal force of a block resting on a pool floor underwater?

There is the force of gravity on the block, the atmosphere, the water pressure o top of the block, but how about between the block and the floor? Would we calculate water pressure pushing up from the ...
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How does thermodynamics affect our lives? [on hold]

How does the second law of thermodynamics affect our lives? Could we live without the second law of thermodynamics? What is the whole purpose of thermodynamics affecting our lives? I know this is a ...
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Perpetual Motion and Thermodynamics [duplicate]

How does the second law of thermodynamics disprove all perpetual motion machines?
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Can the internal energy of an ideal gas ever be zero? Help me understand HW feedback

HW Q: Can the internal energy of an ideal gas ever be zero? Explain. My Response: (implied Yes) wrote ΔU=0 describes a system where *Case a: |Q|= |W|, Q= -W * means heat added to system is ...
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1answer
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Vrms for monotomic, diatomic, and polyatomic molecules

in my notes from class I have that Vrms= sqrt(3kT/m) for a pt molecule Vrms= sqrt(5kT/m) for a diatomic molecule and that Vrms= sqrt(6kT/m) for a triatomic-> higher order molecule but RMS Speed of ...
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Gibbs free energy the 3 equation confusion

Hello can you please help me with thermochemistry? I have been taking chem classes since highschool and they ALL talked about Gibbs free energy, enthalpy, and entropy... even in college I got away ...
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1answer
61 views

What physical law(s) are violated by two masses occupying the same space at the same time?

The two masses have equal mass and equal volume. I think the 2nd law of thermo is violated (because there are less ways to arrange a single mass in space than two), but what other laws could be ...
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Convergent Flow [closed]

Need some help with this fluid dynamics question please. A high-speed drill required cooling to ensure that it does not overheat while in use. To achieve this, high-pressure air is directed through ...
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1answer
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Thermal equilibrium of objects in space

I've read somewhere (not a reliable source though) that an object in space and far enough away from any heat source other than the CMB would eventually cool to 3K, the CMB's temperature, but no colder....
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2answers
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Is spark from spark plug in SI engine (IC engine) not counted as a hot reservoir in Heat Engine?

Are the Heat Engine (HE) and Internal Combustion Engine (ICE) not the same because ICE only exchanges the heat to the surrounding[only one reservoir]? And I have a question what if it's an SI engine ...
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4answers
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Water mixture at different temperatures

Let's say that we mix homegeneously and instantly cold water at $t^\circ $ C and hot water at $T^\circ$ C (like in a water tap) in ratio $p:1$. My question is the following: What is the instant ...
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2answers
115 views

Thermodynamic Entropy seems to be contradictory

For an ideal gas the entropy change with energy is inversely proportional to temperature: This must yield: $$S=\frac 3 2 k_B \ N ln(T)$$ For various reasons, this equation is hard to find. ...
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2answers
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Question on the temperature dependence of the partition function

Let's just say we're looking at the classical continuous canonical ensemble of a harmonic oscillator, where: $$H = \frac{p^2}{2m} + \frac{1}{2} m \omega^2 x^2$$ and the partition function (...
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2answers
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Is the *measured* temperature inside a hollow black body the same if we place a thermometer inside it or let it make contact with the body itself?

Imagine the inside of a black body shell with non-zero thickness. Inside the shell, there is photon gas produced by the shell [at a temperature much higher than zero, say $1000(K)$]. Is there is a ...
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1answer
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Van der Waals cycle calculation [closed]

For the Van der Waals gas we get a cycle consisting of 2 isobaric and 2 isenthalpic processes. We are given $T_1$,$T_3$ and $v_1$,$v_3$. And we want to calculate the efficiency. Attempt of ...
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2answers
55 views

Time for black body to cool to a given temperature

I'm trying to figure out the time required for a blackbody to cool assuming it only looses heat via radiation. I can estimate the mass, specific heat, surface area, emissivity, initial temperature, ...
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0answers
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Maximum achievable mechanical work when heating water

I am doing a question about finding maximum achievable mechanical work when 1L of liquid water is heated from T₁ to T₂ at atmospheric pressure. The solution is $$W = \int_{T_1}^{T_2} \frac{T - T_1}{T} ...
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2answers
73 views

Work extracted from a pressure cooker

How much work can you extract from a turbine connected to a pressure cooker? The situation is modeled as a rigid adiabatic tank of volume $V_{tank}$, which initially contains water at a high ...