12
votes
Does distance exist in thermodynamic coordinates?
This is an old problem to find a natural metric for a thermodynamic process connecting two states. What you are suggesting does not really work because it is not natural in the sense that any other ...
- 464
4
votes
How to convert molar volume to volume?
If you have given
the molar volume $V_\text{m}$ in $\pu{cm3 mol-1}$,
the molar amount in $\pu{mol}$,
you get the volume as $V = n \cdot V_\text{m}\ [\pu{cm3}] = 0.1 \cdot n \cdot V_\text{m}\ [\pu{J ...
- 39.5k
3
votes
Accepted
How can enthalpy of an ideal gas be independent of pressure?
The statement means that enthalpy is independent of pressure, for an ideal gas, if temperature and the amount of matter are both held constant.
For example, if you have 1 mol of idealium on Earth's ...
- 817
3
votes
Accepted
Change in internal energy at constant pressure versus heat released at constant volume
You are first trying to find the internal energy change for the reaction at constant temperature and pressure, given the enthalpy change at the same temperature and pressure. So we are using $$\Delta ...
- 13.1k
2
votes
Accepted
How do you determine the path or process in which a gas attains it's maximum (or minimum) temperature in a cyclic process?
Assuming all the above processes are being performed reversibly over an ideal gas, the gas follows the ideal gas state equation $$pV=nRT$$ in every moment.
As we are interested in temperature in the ...
- 39.5k
2
votes
What are the bubbles and crystals found in sodium acetate hot packs after use and storage in the solid form?
Hi random geologist here with relatives having a heat pack factory
1; bubbles form most prominently the longer you leave the pouch in crystallized state
2; if heated sodium acetate dissolves in its ...
1
vote
Mathematics behind the graph between Gibbs energy and extent of reaction
The math is fairly straightforward if we can start from $$\Delta_r G = \Delta G ^\circ + RT\ln Q$$
Let's use the example of a very simple reaction $\ce{A <=> B}$ with an equilibrium constant of $...
- 10.1k
1
vote
Why does graphite have a higher standard molar entropy than diamond?
The measured heat capacity $C_V$ of graphite at a low temperature, say 100 K is greater than that of diamond. A characteristic measure of the heat capacity is the Debye temperature defined as $\Theta=...
- 30.1k
1
vote
Accepted
Calculation of formation heat given molar heat capacities and reaction enthalpy
You can apply the Hess law (Wikipedia, Libretexts), mere saying the change of enthalpy (or more generally any state variable) depends only on the starting and ending state, not on the path how the end ...
- 39.5k
1
vote
Accepted
What is the difference between standard Gibbs energy and Gibbs energy of formation?
Here are the two definitions again:
$$\Delta G_{Rx} = \Delta G_f^{products} - \Delta G_f^{reactants}\tag{1}$$
$$ \Delta G^o_{Rx} = \sum_i s_i \Delta G_{f,i}^o \tag{2}$$
What exactly is the difference ...
- 39.2k
1
vote
Accepted
Possible error in textbook question? (Heat transfer)
I figured out the problem with my working. I used the following equation earlier:
$(\frac{T_{out} - T_w}{T_{in} - T_w})=exp(\frac{-\pi{d}L}{m{C_p}{R_H}})$
This was the wrong equation to use because it ...
- 21
1
vote
Understanding Rossini and Frandsen experiment for measuring $(\partial u/\partial P)_T$?
One form of the general virial equation of state for a real gas is $$\frac{Pv}{RT}=1+B^*(T)P+C^*(T)P^2+...$$where v is the molar volume. At low pressures, this approaches $$\frac{Pv}{RT}=1+B^*(T)P$$
...
- 13.1k
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