All Questions
21 questions
5
votes
1
answer
228
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Relation between dilution and osmotic pressure
The following question is taken from IAT 2024, an entrance test for research institutes in India at the high school level:
Which one of the following plots correctly describes the variation of ...
- 159
3
votes
1
answer
120
views
Effect of Pressure on the Position of Equilibrium
The following general reaction proceeds with decrease in amount of substance, so increasing pressure should shift the position of equilibrium to the right.
$$\ce{2 A(g) <=> B(g)}$$
But let's say ...
- 47
6
votes
2
answers
851
views
Heat capacity of (ideal) gases at constant pressure
I've come across this article which says that the constant pressure heat capacity is independent of pressure.
It also gives a mathematical explanation which says that any work of an ideal gas at ...
- 471
0
votes
1
answer
311
views
Is fugacity the corrected pressure that should be used in thermodynamical models?
I am a little confused about fugacity and pressure of a gas. In ideal gases, pressure is same as fugacity. But for real gases this is not the case. Here is the link of the question that is the source ...
- 305
2
votes
0
answers
515
views
How to calculate vapor pressure of ethanol at given temperature?
The following is a part of the problem I am struggling with. I think what I need is a vapor pressure of ethanol at $\pu{25 °C},$ but I may be totally wrong.
A reactor is charged with $\pu{60 bar}$ of ...
- 159
0
votes
1
answer
819
views
What causes water to condense when air pressure is reduced?
In this video: https://youtu.be/IyBRGhXBuGw
The cabin pressure is reduced and subsequently a mist is formed.
What exactly is the cause?
2
votes
1
answer
343
views
Does the vapor pressure of a substance depend on the presence of other gases?
The Clausius-Clapeyron equation (CC equation) can be used to find the (saturated) vapor pressure of a substance ie. the gas pressure at which the two phases (vapor + liquid or vapor + solid) reach ...
- 29
2
votes
1
answer
84
views
Finding equilibrium constant for the reaction between non-stoichiometric mix of gaseous components
$$\ce{CH3OH(g) + NOCl(g) <=> CH3ONO(g) + HCl(g)}$$
The volume of the container is $\pu{433 cm^3},$ $T = \pu{50 °C}.$ Methanol was added until the pressure was $\pu{50.1 mbar},$ then $\pu{0.059 g}...
- 1,095
3
votes
2
answers
296
views
Effect on mass when decreasing pressure in equilibrium reaction
For example, if we have the reaction:
$$\ce{A + B <=> C}$$
And the volume is decreased, the pressure would increase. Hence, according to Le chatelier's principle, the system will partially ...
- 87
-1
votes
3
answers
827
views
Can work be done on a body when temperature and pressure are changed without changing its volume?
Can work be done on a gaseous system when temperature and pressure are changed without changing it's volume?
In chemistry the formula of work is always $p\,\mathrm dV,$ whereas we can also do work on ...
1
vote
1
answer
2k
views
Clausius–Clapeyron equation: shape of phase diagrams makes no sense
I am trying to model the melting point of a substance at varying pressures (ranging from very small to very very large). All I am trying to do is make an equation that relates melting temperature to ...
-2
votes
2
answers
699
views
How do you manage to liquefy a gas by applying only pressure? [closed]
How can you liquefy a gas by applying only pressure? To increase the pressure of a gas you need a compressor, and when the compressor does work on the gas , it will increase his pressure but at the ...
- 21
4
votes
2
answers
726
views
Regarding units of water potential and chemical potential
If water potential is nothing but the chemical potential of a given solution, then why do their units differ?
If the unit for the latter is taken as 'Energy per molecule' (which makes sense to me ...
- 49
3
votes
1
answer
637
views
Isothermal vs adiabatic compression of an ideal gas [closed]
Could someone please explain these specific questions physically (especially the first question!)? I understand the corresponding mathematical proofs, but not the physical reasoning? I have looked ...
- 33
1
vote
2
answers
603
views
Which pressure is used for calculation of standard enthalpy change of the reaction with two or more gases?
Standard state conditions for standard Gibbs free energy change stipulate (among other conditions) that the partial pressure of each gas is $\pu{1 bar},$ e.g. for the reaction
$$\ce{2 A(g) + 3 B(g) &...
3
votes
4
answers
2k
views
Enthalpy of a reaction changes with temperature, does this mean bond strengths change with temperature?
During chemical reactions, the bonds between atoms break or form to either absorb or release energy. The result is a change to the potential energy of the system. The heat absorbed or released from a ...
3
votes
1
answer
290
views
Thermodynamics : Work Done by a Gas
Suppose in a piston in which there is a gas, the gas exerts pressure P on surroundings, whereas the surrounding exerts a pressure $P[ext]$ on the gas.
In order for the gas to expand, P must be ...
- 329
1
vote
1
answer
1k
views
Partial Pressure and Partial Molar Volume
When we define partial pressure and partial molar volume of a gas in a mixture, suppose $P$ is partial pressure of a gas in a mixture and $V$ is partial molar volume
then why the following equation ...
- 329
1
vote
1
answer
182
views
When fugacity and z-compressability equations instead of Gibbs free energy equations?
In very high pressure environments such as mud circulating systems, conditions for polymers contain fugacity/z-compressability criteria instead of Gibbs free energy, more in the answer. So
When ...
- 256
5
votes
4
answers
467
views
Will the total equilibrium pressure increase in gas phase reaction PCl5(g) ⇌ PCl3(g) + Cl2(g) after chlorine is removed?
Will the total pressure be greater than the initial equilibrium pressure if all $\ce{Cl2}$ is removed and the following reaction is allowed to re-equilibrate?
$$\ce{PCl5(g) <=> PCl3(g) + Cl2(g)}$...
- 53
2
votes
2
answers
2k
views
How to find the change in internal energy (q+w) for an expanding monoatomc ideal gas?
If a monoatomic ideal gas simultaneously expands against a constant external pressure and drops in temperature, how do you find the internal energy change?
Known values are: $T_1$, $T_2$, $p_1$, $p_2$,...
- 41