The chemical-potential tag has no wiki summary.
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How much Bicarbonate of Soda and Vinegar would I need to reach space?
So here is my problem - as part of my job I present some science demonstrations to children and one of the tricks I regularly use is the bicarb/acetic acid rocket. I thought the other day that a ...
4
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1answer
414 views
Energy per particle vs. chemical potential vs. evaporation energy
There is a system of N particles. They interact and are bound together with a binding energy Eb (or potential energy). To characterize the system there are multiple terms
Energy per particle Eb(N)/N
...
4
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1answer
176 views
Voltage drop over a cell membrane
Again, a problem from exam preparation:
[A] cell's membrane allows sodium ions to pass through it, but not chlorine ions. The cell is placed in a salty solution with a ten times higher ...
3
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1answer
375 views
What does activation energy actually do?
Spontaneous (exothermic) chemical reactions often require a push from the addition of externally supplied energy. This energy is often called activation energy. What does activation energy actually ...
3
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1answer
152 views
Why do hydrogen atoms attract?
That is, why is the potential energy with the orbitals overlapping less than with the Hydrogen atoms 'independent'.
Similarly, why is a noble gas configuration stabler than if an electron were to be ...
2
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1answer
41 views
Chemical potential of a Bose gas
In my course, there is this fact :
In a Bose gas, the chemical potential $\mu$ must always be lower than
the smaller level of energy $\epsilon_0$.
I find this strange, because if we put a Bose ...
2
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1answer
387 views
Internal Energy and entropy in a open system
Here http://en.wikipedia.org/wiki/Internal_energy we can read
$$U= TS-PV+\sum_i \mu_i N_i$$
Let's suppose i=1 and a ideal gas. We know:
$$U=N/N_A c_v T$$;
$$PV=NKT$$;
$$\mu=\frac{\partial ...
2
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2answers
83 views
Ashcroft Mermin Eq. 17.47ff
In "Solid State Physics" by said authors, Eq. 17.46 is
$$ \rho^{ind}(\textbf{r}) = - e[n_0(\mu + e\phi(\textbf{r})) - n_0(\mu)]$$
and then the authors write
In the present case we assume that ...
2
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1answer
168 views
How does the internuclear repulsion vary in Hydrogenic atom collision?
Hydrogen fusion requires two hydrogen nuclei to get close enough (typically a few fm) to fuse. Much of the problem of creating a fusion reactor is overcoming the Coulomb repulsion between a pair of ...
1
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1answer
72 views
Is particle number a problem for formulating statistical physics in a mathematically rigorous manner?
Quantities like the chemical potential can be expressed as something like
$$\mu=-T\left(\tfrac{\partial S}{\partial N}\right)_{E,V}.$$
Now the entropy is the log some volume, which depends on the ...
1
vote
1answer
444 views
Calculating the derivative of the average number of particles by the chemical potential
This should be a trivial calculation but somehow I have managed to get myself confused about this.
The grand partition function is:
$\mathcal Z = \sum_{N=1}^\infty \sum_{r(N)} {\text e}^{-\beta E_r ...
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2answers
362 views
What is the physical or mathematical meaning of the Gibbs-Duhem equation?
The Gibbs-Duhem equation states
$$0~=~SdT-VdP+\sum(N_i d\mu_i),$$
where $\mu$ is the chemical potential. Does it have any mathematical (about intensive parameters) or physical meaning?
0
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1answer
99 views
Ways to experimentally control the chemical potential of a solid state system
When working in the grand canonical ensemble we write the grand potential as $\Omega = \Omega (T,V,\mu)$. In this case we are taking the chemical potential $\mu$ to be an independent variable. This ...
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0answers
18 views
Flow of the component of a hidrostatic system
I have a problem that asks me to prove, from notions of thermodynamic chemichal potential, that at constant temperature, air (or any component of a hidrostatic system) will flow to lower pressures, ...
0
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1answer
45 views
Anions in Voltaic cells [closed]
Is it true that both aqueous liquids contained in a voltaic cell need to have the same anion?
All the pictures dipicted in wiki have that feature. However, is it possible to have it such that the ...
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3answers
1k views
How does evaporation affect the temperature of the air?
A wet object or a volume of water will decrease in temperature due to the effect of evaporation. We understand this to be because of the molecular kinetics, where the faster water molecules escape ...
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4answers
821 views
What is potential at a point?
What does potential at a point exactly mean? My teacher tells me that current flows from higher potential to lower potential but when I ask him the reason, he fails to give me a convincing answer.
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