# Questions tagged [isotherm]

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I was reading about the Freundlich adsorption isotherm and when I read the equation I was quite confused. It states that $$x/m=k(p)^{1/n}$$ So basically x is mass of the adsorbate adsorbed, m is mass ...
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### Doubt regarding isothermal reversible process- Thermodynamics

Since its a reversible process, I can say $P_{ext}=P_{int}\pm dP$ so now $W_{int}=\int_{V_1}^{V_2} P_{int}dV$ My question is why can't I assume $P_{ext}=P_{int}$ here and take it as a constant ...
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### Why is the work done on the system not equal in frame of gas and surroundings?

Consider an isothermal irreversible process for an ideal gas in a cylindrical container closed with a piston (system). Initial and final states are $(P_1,V_1,T)$ and $(P_2,V_2,T)$ respectively. ...
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### How exactly is heat supplied in an isothermal process

How exactly is heat supplied in an reversible isothermal process. If the temperature of system and surroundings always remains the same, then how come surrounding is supplying heat? I studied that T ...
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### Do "pseudo Van der Waals" gases exist?

In college, when deriving the Langmuir isotherm for gas-solid adsorption, the professor proposed a modified version of the Van der Waals state equation, what he called the "pseudo Van der Waals ...
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### Understanding isosteric enthalpy (heat) of adsorption

I am trying to understand what is isosteric heat of adsorption. Based on van't Hoff equation: $$\left(\frac{\partial \ln K}{\partial T}\right)_θ = \frac{ΔH^\circ}{RT^2}$$ and $ΔH^\circ$ is defined ...
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1 vote
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### Virial expansion of real gas equation and volume work

Hi I am currently working on a thermodynamics problem, and it asks me to first find the volume work done on a gas that behaves like the simplified Dieterici equation (see below) predicts on isothermal ...
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### Can PV vs P plot be called an isotherm?

Normally we call plots drawn at constant temperature as isotherms, e.g. $P$ vs $V$ plot, Langmuir isotherm etc. Using that logic, shouldn't the $PV$ vs $P$ plots also be called isotherms? Personally, ...
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1 vote
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### Justifying assumptions about method to find equilibrium pressure for co-existence of graphite and diamond

The standard state Gibbs free energies of formation of $\ce{C(graphite)}$ and $\ce{C(diamond)}$ at $T = \pu{298 K}$ are $\pu{0 kJ mol-1}$ and $\pu{2.9 kJ mol-1}$, respectively. The conversion of ...
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### Entropy of free expansion and isothermal process

Let me tell what I understand of the concepts on which the question is based first. Heat is a flow of energy that takes place due to a temperature gradient. When doing reversible isothermal expansion ...
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### Interpreting a thermodynamics equation using a picture

Given $$\frac{\partial \Gamma}{\partial p}\Bigg|_{t} =\frac{\partial \Gamma}{\partial p}\Bigg|_{v}+\frac{\partial v}{\partial p}\Bigg|_{t}\frac{\partial \Gamma}{\partial v}\Bigg|_{p} \tag{1}$$ where \...
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The following problem was asked in JEE Mains 2020 (Sept 2, Shift 1), The mass of gas adsorbed, $x$, per unit mass of adsorbate, $m$, was measured at various pressures, $p$. A graph between \$\log\frac ...