Unanswered Questions
947 questions with no upvoted or accepted answers
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Curtin-Hammett principle to evaluate alkene insertion
Given an unsymmetrical alkene in a simple non-stereoselective catalytic hydrogenation reaction. If one would want to investigate the nuances in the catalytic cycle of a dihydride complex leading to ...
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Has a concept of temperature ever been defined in the context of a single atom?
I wonder if this answer to What would happen if we supercool and then superheat an atom very abruptly? goes far enough.
I almost wrote the comment:
I don't think we can even talk about the ...
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Whether the entropy change of the system is positive or negative
$$\ce{N2(g) + O2(g) → 2NO(g)}$$
My thinking: since gases are combined together, so there randomness or disorder gets decreased. Hence the sign of entropy change of the system should be negative.
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Calculating ΔH from bomb calorimetry
Suppose we carry out a reaction in a bomb calorimeter whose starting temperature is $298.15\ \mathrm K$. Here we assume $\Delta V$ is close enough to zero that we consider the process to be at ...
CommunityBot
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4
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Extrapolating from a calorimetry lab to find a new delta T with different volumes and grams of substance
So, we just finished an AP chem lab where the question was basically:
Given the results of the lab were that $\pu{5 grams}$ of $\ce{CaCl2}$ and $\pu{45ml}$ of water produced a $\pu{13.33 ^\circ C}$ ...
CommunityBot
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Meaning of electrochemical vs nonelectrochemical steps
Can someone please explain to me what is meant by an electrochemical reaction step and how it differs from a nonelectrochemical reaction step in the same overall reaction in the context of ...
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If dG is a state function, why do reversible and irreversible paths differ?
For a reversible process at constant T,P in a closed system with no non-expansion work dG = 0. For an irreversible process under the same conditions, dG < 0. Since dG is a state function I would ...
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Choosing electrodes for corrosive environments
Background
I'm building a watering robot for my household plants. For the purpose of measuring the moisture content of the plant I intend to use a resisitive approach where I pass an electric current ...
CommunityBot
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Can a droplet of formalin evaporate in midair while falling?
I am designing an evaporator for use in an enclosed environment. Due to the hazardous nature of formaldehyde, I want my evaporator to be wick-free.
The environment in which the evaporator will be used ...
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Can anyone explain this condensation pattern?
What is the hair-like polymer that condenses on the caps of the plastic cell vial? Inside vial are cells in a mixture of FBS and DMSO. The vials were frozen slowly in a special isopropanol-filled ...
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Is electric current always necessary to make cathodic protection possible?
Can a cathodic protection system still work if there is no current between the anode and cathode?
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Why does the electrolyte used in Lechlanché cell turn blue?
In my school there are jars which are turned into Lechlanché cells. Basically the cell has aqueous ammonium chloride solution as the electrolyte which is obviously transparent in the beginning. The ...
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Conductivity of electrolyte solution
I found a relationship online between the conductivity of electrolyte and current.
$$i = F \sum_i z_i N_i = F^2 \left( \sum_i z_i^2 u_i c_i \right)\nabla\phi = -\kappa\nabla\phi \qquad \kappa = F^2 \...
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Theoretical temperature change in lime hydration
Calcium oxide (quicklime) and water have an exothermic reaction
$\ce{CaO + H2O \rightarrow Ca(OH)_2} \quad \quad \Delta H^{\circ}_f=-65.3 \; \mathrm{kJ \cdot mol^{-1}}$
Assume that I have 1 kg of ...
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An alternate purification process for sugar separation form bee honey?
Bee honey contains 75% sugars (Fructose, Glucose, Maltose, Sucrose and others), some water and low amount of different compounds (up to 5%) Wiki.
Basic purification is done by addition of phosphoric ...
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