Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, radiation, and physical properties of matter. The behavior of these quantities is governed by the four laws of thermodynamics which convey a quantitative description using measurable macroscopic physical quantities, but may be explained in terms of microscopic constituents by statistical mechanics. Thermodynamics applies to a wide variety of topics in science and engineering, especially physical chemistry, biochemistry, chemical engineering and mechanical engineering, but also in other complex fields such as meteorology.
Historically, thermodynamics developed out of a desire to increase the efficiency of early steam engines, particularly through the work of French physicist Nicolas Léonard Sadi Carnot (1824) who believed that engine efficiency was the key that could help France win the Napoleonic Wars. Scots-Irish physicist Lord Kelvin was the first to formulate a concise definition of thermodynamics in 1854 which stated, "Thermo-dynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies, and the relation of heat to electrical agency."
The initial application of thermodynamics to mechanical heat engines was quickly extended to the study of chemical compounds and chemical reactions. Chemical thermodynamics studies the nature of the role of entropy in the process of chemical reactions and has provided the bulk of expansion and knowledge of the field. Other formulations of thermodynamics emerged. Statistical thermodynamics, or statistical mechanics, concerns itself with statistical predictions of the collective motion of particles from their microscopic behavior. In 1909, Constantin Carathéodory presented a purely mathematical approach in an axiomatic formulation, a description often referred to as geometrical thermodynamics.
By using the given relationship that S=a/T --(1) along with the equation ∫ (delta Q rev)/T=∫dS -- (2) I found out that my answer for the value of Q is mc*ln (T2/T1)*a upon equating (1) & (2).
But the solution is instead given as Q=a*ln*(T1/T2).
I would be grateful if someone would point out...
The question is given in 3 parts.
For first part, process is isochoric so Work done=0. We know here that at end of the process (a), T2=T1 while V remains constant (we can take it as V1) so P2=2P1.
For second part, process is isothermal so T is constant. At end of process we reach P1 again from...
I just finished rereading the great "A Brief History of Time". To me, what stands out the most in this book, is its ability to keep raising questions while you read it. This thought came up. It's been stuck in my mind for days, so I will humbly post it here to get some feedback. Please forgive...
I am a nanobiology student about to start her 2nd year. This year I only had 2 physics courses and I did pretty bad in both. As I start my second year I would like to be very prepared in physics since we will have way more of this subject. Are there some books or tips you have to catch up on...
For the first part, I have expressed it in the following differential form- dU= delta (Q) + BdM
Now for the second part I am having major confusion. I know that B corresponds to P and M corresponds to V as generalised force and generalised displacement respectively for a Paramagnetic substance...
Hi Everyone,
I am looking to find how much heat can be stored in a concrete pipe of roughly 0.3-0.4m diameter, and an internal diameter of 0.05m. Air will travel through the internal diameter at 500°C and 17.5bar which will provide the heat for the pipes. This system will then be reversed so...
I'm not looking for someone to tell me the answer, just help steer me in the right direction.
I feel like I need to find the air density or air velocity at entry to proceed, but I'm unsure
any help and guidance is greatly apricated!
Solution attempt :
Option :
I am sure that my work is wrong. But, I must add solution attempt in PF that's why I just added that. How can I solve the problem?
So I am a fan of astronomy, cosmology and astrophysics from a FAR. The math is way beyond my abilities but I like to just sometimes read and think about the very small parts I am able to comprehend. So my hats off to all of you that are able to fully enjoy this stuff, you're very lucky...
I have heard from a knowledgeable physics proffessor, time exists independently and it is not a consequence of arrow of time. Could some body explain this?
In most experiments of SR, we look at atomic and subatomic particles or the frequency of EM radiation.
The Haefele-Keating experiment looked at the resonance of cesium atoms stimulated by a certain EM frequency
https://en.wikipedia.org/wiki/Hafele–Keating_experiment
The Ives-Stillwell...
as the process has been given as an adiabatic one, dQ=0, further attempt is given in the attached files, but the problem is I got X=1 while the official key states it to be X=2.05, could anyone explain why
If we look at system at constant temperature and volume which is galvanic cell, first law of thermodynamics states: $$ dU = dQ + dW' $$
Where W' is electrical work done by galvanic cell and Q is heat exchanged with surroundings.
As far as I know electrical work is work done by electric field...
So firstly, I don't understand if the mass flow rate is for steam or for water. If it is for water, I know I can find the heat transfer rate using equation:Q=mcdeltaT.
But then I don't know how to find h (the average heat transfer coefficient) because I don't know the surface area (As). I can...
One of the most fundamental equations in chemical thermodynamics states: $$ \Delta_rH_m^⦵ = \Delta_rG_m^⦵ + T \Delta_rS_m^⦵ $$
If we look at this equation in context of net chemical reaction in electrolytic or galvanic cell, it is usually interpreted as follows: Enthalpy of reaction denotes...
This is the problem statement:
We can start by writing ##
(\star d \star d \xi)_a = - \nabla^b (d\xi)_{ab} = - \nabla^b \nabla_a \xi_b + \nabla^b \nabla_b \xi_a = 2\nabla^b \nabla_b \xi_a
##. Then with ##\nabla_a \nabla_b \xi_c = R_{cbad} \xi^d = -R_{bcad} \xi^d## we can contract over...
'Every non-equilibrium state of a system or local subsystem for which entropy is well defined must be equipped with a metric in state space with respect to which the irreversible component of its time evolution is in the direction of steepest entropy ascent compatible with the conservation...
It is a long problem, but it is simple to understand.
I am having trouble with part A. My attempt:
Pressure outside > pressure inside container. pV = constant (isothermal). At equilibrium, all gases are at atmospheric pressure. Because it is quasi-static, the pressures of both compartments are...
Does anyone know of any good papers/lectures/textbooks/etc that discuss the physical and mathematical principles that explain the structure and motion of clouds? Thanks.
Well, internal energy is the sum of the kinetic and potential energies of all the molecules within a given mass of a substance; this energy is associated with the random, disordered motion of the molecules.
An example of internal energy is compressed gases; since gases occupy the total volume...
In the book for our thermodynamics, it states that a process that is internally reversible and adiabatic, has to be isentropic, but an isentropic process doesn't have to be reversible and adiabatic. I don't really understand this. I always thought isentropic and reversible mean the same thing...
I have solved this question and it seemed pretty easy, but I got an extremely large number for the mass flow, I had to post the question here to make sure I did it correctly. Any help will be appreciated.
So I calculated the final and initial pressures using the given eqns, ended up with the final pressure of 96629 and initial pressure of 62639.
Then I used the PV=nRT eqn to calculate the final and initial temperatures. T=P*V/(n*1.5*R).
I got an initial temperature of 81.79 and a final...
In this problem, the method used to solve the question is to equate pdV with change in internal energy. This implies an adiabatic process as Q = 0? (not sure about this claim) However, why is it not correct to simply apply the PV^ϒ = constant formula?
Thank you.
I have solved the first 2 parts.
For the 3rd part, I have obtained the equation:
T(x) - T0 = (T1 - T0)e^(-Φx/fc), where f = fm in the question.
How do I obtain that expression for H?
Thank you!
I add a Figure with the problem and solution. I have difficulty with a solution to the given problem. Why ##F=-kx=Adp##, I do not understand minus sign because we are working with scalars not vectors. It is correct to say that
##\vec{F}=-kx\vec{i}##, but is not correct to say that ##F=-kx##. Can...
In answering questions (a.) Why heat intake in this system is
## \Delta Q_{sys} = ( \Delta Q_{hot water} + \Delta Q_{cold water} ) / 2 ##
where.
##\Delta Q_{hot water} = c(T_1 - T_f) ##
##\Delta Q_{cold water} = c(T_2 - T_f) ##
I think T or T_f should be between T_1 and T_2
But why is the...
Since this is a two-state paramagnet where N = 40, therefore the microstate is ##40^2##? But I am not sure how to proceed to count the number of macrostates? Because from what I understand of what a macrostate is, shouldn't there a specific outcome to be stated in order to determine how many...
i can't manage to grasp the concept of PV work in thermodynamics, for example we all know that W= integral(F*dx) like here
but this says that, at the end, W doesn't really depend on the gas temperature or reversible process crap
at the end W is simply a constant, atmospheric pressure is...
I found this interesting thermodynamics problem on another site. I thought PF members might find it challenging to attack. I'm not asking for help since I've already solved it. So pease feel free to present your entire solution if you desire.
Chet
Do particles have air in between them in the ideal gas model?
I think the answer is 'no, but I am not quite sure about the explanation. Is it because in an ideal gas model, the volume of the particles is negligible? Thank you.
Hello there,
Can anybody recommend me a good thermodynamics textbook? I prefer the ones that have a deep or complete (if possible) discussion about the theoretical aspect of thermodynamics, and the mathematical aspect as well.
Thank you
FIRST TYPE: REVERSIBLE PROCESS At the temperature of 127 ° C, 1 L of CO2 is reversibly compressed from the pressure of 380 mmHg to that of 1 atm. Calculate the heat and labor exchanged assuming the gas is ideal. Q = L = - 34.95 J
CONDUCT 380 mmHg = 0.5 atm L = P1 * V1 * ln (P1 / P2) = 0.5 * 1...
Consider a reversible ideal gas cycle consisting of: 1. An isochoric heat addition, 2. An isothermal expansion to the initial pressure, and 3. An isobaric compression to the initial volume. What, if any, is the difference in net work done by the gas in the cycle if the isochoric heat addition...
Consider instead a thermally insulated container of volume V with a
small hole of area A, containing a gas with molecular mass m. At time t = 0, the density is ##n_0## and temperature is ##T_0##. As gas effuses out through a small hole, both density and temperature inside the container will...
Hi,
I have been studying physics again and I was looking for a good introductory book for thermodynamics. I wanted to know if there is a book in thermodynamics that would be the equivalent to "An introduction to Mechanics" by Kleppner/Kolenkow, or "Electricity and Magnetism" by Purcell? These 2...
Hi, there is no other topics in my adventure in Feynman Lectures that makes me so loss in thoughts (https://www.feynmanlectures.caltech.edu/I_44.html). I seem to understand every sentence. But the whole thing is completely unintelligible. Let me start by asking one fundamental question. I am...
Hi,
I have been researching how to protect my card collection from the unlikely event of a house fire, however there is not enough data for me to estimate whether my set up is adequate or not. If anyone could approximate anything here without knowing all the exact variables (r-values) that...
For part (a), I used this formula
where where the i's represent the substance being used and mu_i^0 represents some reference potential. However, to my knowledge this simply calculates the change in chemical potential from one state to another which is not of much help in finding the relative...
At some point, in Physics (more precisely in thermodynamics), I must take the divergence of a quantity like ##\mu \vec F##. Where ##\mu## is a scalar function of possibly many different variables such as temperature (which is also a scalar), position, and even magnetic field (a vector field)...
I am struggling to understand Callen's explanation for stability, I understand that the concavity of S(U) must be negative because otherwise we can show that this means that the temperature increases as the internal energy decreases (dT/dU<0) but I cannot understand equation (8.1) which...
I have the Cp of Benzoyl peroxide (BPO) in gas form (454.39 J/molK). What approximation could I make to find the Cp of solid BPO as I cannot find this info online? thanks
I know that when it is ΔG>0 , it means there is no spontaneity, when ΔG=0 there is equilibrium, and when ΔG<0, there is spontaneity. But what happens when this is in the context of partial molar properties, when G is molar?
I suppose molar ΔG is referred to a solution. Right? In that case, is...
For part 1. I need to find the temperature, I rearranged the equation so that:
T = pV/nR
(28000000)(0.45) / (28.96)(8.314)
This gives me a value of 52331.4
I am unsure where the units I have used in the equation are correct.
I have used pa for pressure, or should I be using kpa? this would...
Naively there is a conflict between CPT symmetry being at heart of fundamental physics models like QFT, and 2nd law of thermodynamics: saying that entropy grows toward future.
Is there really a conflict here - so is physics symmetric or not? How to understand it?
Personally I disagree with that...
I tried by one way, seems ok and makes sense, but i am not sure if it is valid yet.
$$P_{a} = c_{a}V_{a}^{(-\gamma_{a})}$$
$$P_{b} = c_{b}V_{b}^{(-\gamma_{b})}$$
$$(Pa,va = Pb,vb)$$
$$\frac{c_{a}}{c_{b}} =\frac{[V_{b}^{-\gamma_{b}}]}{[V_{a}^{-\gamma_{a}}]} = V^{-\gamma_{b}+\gamma{a}}$$
Now this...
V = V(n,P)
PV = nc
dV = (-cn/P²)dP + (c/P)dn
dW = (cn/P)dP - (c)dn
This was how i tried to attack the problem, but it will end with log and probably it is wrong, any tips to fix it?