Unanswered Questions
712 questions with no upvoted or accepted answers
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Is there an adhesive that is not dissolved by acetone?
I am trying to glue glass sheets together to make a sealed 13" x 13" x 13" box. Inside this box there would be acetone gas used to melt 3D printed parts to make them more durable. Acetone will remove ...
- 1
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Reconciling Flory-Huggins Theory with Le Chatelier's Principle
(I discuss the Flory-Huggins parameter as chi from here onward). So I had learned in class that when discussing polymers the Flory-Huggins Theory helps us figure out whether mixing is ...
- 51
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432
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Compounds that Liberate Hydrogen from Water, Reversibly
I'm working on a paper which provides an overview of all the current methods for storing hydrogen gas as part of a renewable energy system, and I understand compressed gas and metal hydride storage ...
- 165
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113
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Describing evaporation without entropy -- what about Helmholtz?
I have in mind a rigid, impervious, heat-insulating vessel containing a monatomic liquid and vacuum. The vessel has an insulating forcefield inside, exactly at the surface of the liquid. It can be ...
- 399
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967
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Entropy Change of Resistor
A very large swimming pool filled with water of temperature equal to $20\ \mathrm{^\circ C}$ is heated
by a resistor with a heating power of $500\ \mathrm{W}$ for $20$ minutes. Assuming the water in ...
- 1,169
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553
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What does the equilibrium constant mean for reactions with very small concentrations?
When you calculate the equilibrium constant for a reaction with a higher concentration of reactants, the answer is fairly intuitive. For example, for the reaction:
$$\ce{A + B <=> C}$$
when we ...
- 22.5k
4
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142
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Solubility or reactivity of tantalum carbide and potassium polyselenides?
It is probably an unexplored system, but is there anything known about the low temperature thermodynamic equilibrium state of this?
By 'tantalum carbide', I mean $\ce{TaC}$, and by potassium ...
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With two reagents common on Mars, fluorite and CO2, how would I produce carbon tetrafluoride?
The hypothetical terraforming of Mars would require the heating of the atmosphere. A commonly suggested method is the in-situ production of fluorocarbons, powerful greenhouse gases.
For example, ...
- 6,801
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111
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How to estimate the mobility constant and the surface energy parameter in the Cahn-Hilliard equation?
As a mathematician, I want to simulate phase separations with the Cahn-Hilliard equation
$$
\frac{\partial c}{\partial t} = M \Delta \bigg(\frac{\partial \mu}{\partial c} - \kappa \Delta c \bigg),
$$
...
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445
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Why is the relationship between molar mass and boiling point for alkanes a square root relationship?
I plotted the boiling point of alkanes against their molar mass and found the following trend:
I expected the trend would be linear, since (based on my understanding of what I've learned in class so ...
- 49
4
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1
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Variation of conductance of saturated aqueous solution with temperature
The following question was asked in JEE Mains 2020:
Let $C_{\ce{NaCl}}$ and $C_{\ce{BaSO4}}$ be the conductances (in S) measured for saturated aqueous solutions of $\ce{NaCl}$ and $\ce{BaSO4}$, ...
CommunityBot
- 1
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176
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Why is there a large increase in volume when an alkali metal is dissolved in liquid ammonia?
My teacher said unexplainedly that when alkali metals dissolves in liquid ammonia, there is a large increase in the volume. I found a paper that confirms this fact [1]:
In the course of recent ...
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4
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237
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What is the Gibbs free energy change of physisorption?
In most sites I find online, I see that the Gibbs free energy of adsorption is negative. But, it is also said that physisorption is a reversible adsorption, suggesting that $\delta G=0$ which ...
- 71.6k
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2
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1k
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Entropy change during electrolysis of water
Consider the electrolysis of water reaction:
$$\ce{H_2O -> H_2 + 1/2O_2}$$
At room temperature and atmospheric pressure, the change in enthalpy of this reaction is $\Delta H = \pu{+286 kJ mol-1}$. ...
- 6,801
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Regarding Ellingham diagrams
In my textbook, the following information is given about Ellingham diagram:
The interpretation of $\ce{\Delta_rG^\circ}$ is based on ${K}$ ($\ce{\Delta G^\circ = -RTlnK}$). Thus it is presumed that ...
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