All Questions
Tagged with adsorption thermodynamics
10
questions
6
votes
0
answers
82
views
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 ...
- 159
4
votes
1
answer
255
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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 ...
- 766
2
votes
1
answer
355
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Why does chemisorption decrease with increasing temperatures?
Why is it that chemisorption decreases with higher temperatures?
The explanations I found online were quite vague and one of them cited Le Chatelier's principle, but I thought chemisorption is an ...
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1
vote
2
answers
698
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Why enthalpy of adsorption is negative?
I have already read Is adsorption exothermic, and if so, why? but it didn't answered my query.
To illustrate, let's take a hypothetical vacuum space. In that space, there is a solid and a gas, the ...
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2
votes
0
answers
2k
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Why increase in enthalpy leads to increase in entropy? [closed]
Given statement: Enthalpy of adsorption is the strength at which molecule (say $\ce{H2}$) is bound to the adsorbent (say some metal center). For a free $\ce{H2}$ molecule, the entropy contribution is ...
- 155
0
votes
2
answers
146
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How does physical adsorption of mixed gas occur on solid? (eg I mean how the gas molecules of compete each other for a slot on solid surface)
I am working on sorption phenomenon of gases (including inert gas) on coal seam surface.
For a mixture of 2 gases at a certain pressure, carbon dioxide and methane, for instance, $\ce{CO2}$ is ...
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10
votes
6
answers
12k
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Why does chemisorption increase with rise in temperature, even though it is an exothermic process?
Chemisorption is exothermic process, but still it increases with increase in temperature. Why?
I know that there needs to be a minimum activation energy to be achieved in order to initiate ...
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12
votes
1
answer
10k
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Is adsorption exothermic, and if so, why?
Why is adsorption exothermic?
The explanation given in my textbook is:
For a process to be spontaneous, the thermodynamic requirement is that, at constant temperature and pressure, $\Delta G &...
- 7,804
15
votes
4
answers
1k
views
Relative strength of desiccants
Is it meaningful to characterize the relative strength of desiccants? For example, is there a measure of hygroscopy, or an ordering of desiccants, such that higher ones will always dry lower ones?
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- 3,340
18
votes
5
answers
28k
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Why is Charcoal such an excellent adsorbent?
Charcoal (also activated charcoal) is known to adsorb a huge variety of substances including a variety of paints, dyes and many different kinds of ions. Moreover, the amount of adsorption at normal ...
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