# 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].

12,371 questions
Filter by
Sorted by
Tagged with
14 views

### What does integrating the probability density function over all phase space gives us?

For a system of N-3D particles, we have 6N D.O.F and therefore a 6N dimensional phase space. I know that one point in phase space represents a possible state of the system. I also understand that a ...
10 views

### Question about the solution of problem 7-62 Thermodynamics Cengel 8th

A $25-kg$ iron block initially at $350°C$ is quenched in an insulated tank that contains 100 kg of water at $18°C$. Assuming the water that vaporizes during the process condenses back in the tank, ...
20 views

### Phase space, ensemble of systems and probability density function

I am trying to understand the concept of phase space in statistical mechanics. I can understand that a system, with $N$ total degrees of freedom, can be in different states, which correspond to ...
23 views

### Entropy change of an elastic cylinder

We had in our thermodynamics class an example regarding the entropy change of a rubber cylinder.It has an initial length $L_0$ and after we stretch it it has a final length $L_f$.A thermodynamic state ...
36 views

5k views

### Why do we need insulation material between two walls?

Consider a slab made of two walls separated by air. Why do we need insulation material between the two walls. Air thermal conductivity is lower than most thermal conductivities of insulating material ...
43 views

### Efficiency of electric heaters

I was reading this question. A person was asking what is the efficiency of an electric heater, and to sum up, people were answering "All resistive heating, can be considered to have 100% ...
7 views

### Does having a large liquid surface effect evaporation stability?

Imagine I have a metal block in a vacuum chamber, which is then heated by a laser. It is heated past its melting point until a small melt pool is present at the location of the laser. My question is: ...
52 views

### Interpretation of probability in Statistical Mechanics

In statistical mechanics, in particular the canonical ensemble, the probability of the system to have a particular state is given by : $$P_i=\frac{e^{-\beta E}}{Z}$$ Here $Z$ is the partition function ...
30 views

### What is wrong in my attempt? [closed]

The following question is a question from KTG and Thermodynamics. In this question I tried to solve it by finding the work done by the gas and equating it to $nR\Delta T$ but the answer turns out to ...
53 views

### How can I calculate to how fast heat is transferred from the surface of a massive hall to the ceiling?

I have asked something similar to this question before but couldn't get an useful answer: https://worldbuilding.stackexchange.com/questions/213240/i-am-building-an-isolated-indoor-temperate-rain-...
29 views

### Can Brownian motion explain why white smoke moves around in the air?

Can Brownian motion explain why white smoke (fume) generated by chemical reactions moves around in the air?
216 views

### What does ultra-rarefied gas mean?

Without using any math, can you explain to me what a rarefied gas is? And then what an ultra-rarefied gas is? I'd like to understand it from a conceptual level if you can make connections to other ...
47 views

### Exact heat capacity of the 2-dimensional Ising model

The following is a section from the book Newman, M., and G. Barkema. "Monte carlo methods in statistical physics" New York, USA (1999). and then: From those two quotes, it seems that there ...
Suppose we have a system filled with $N$ particles. There are $k$ energy levels in this system, labeled by $\epsilon_i$, each with a degeneracy of $g_i$. Let us imagine $n_j$ particles out of these $N$...