Unanswered Questions
524 questions with no upvoted or accepted answers
7
votes
0
answers
135
views
Metal hydrolysis and equilbrium constants from stability constants
Problem: I want to create minimum solubility plots for a series of metal hydrolysis species against pH (below). But I cannot reconcile literature stability constants and equilibrium constants.
Context:...
6
votes
0
answers
171
views
Which xylenes, if any, are immiscible with DMSO?
"Xylene" is reported to be immiscible with dimethyl sulfoxide (DMSO), according to a few solvent miscibility tables found online (chart 1, chart 2, chart 3). I have tried to locate some ...
6
votes
0
answers
164
views
Why is supersaturated sodium acetate so (meta)stable?
Sodium acetate is a common example used in general chemistry lectures to illustrate the idea of supersaturation, and that precipitation of a supersaturated solution can be initiated by a seed crystal. ...
6
votes
0
answers
67
views
Using Le Chatelier's Principle to Change Mechanical Energy to Chemical Energy
I was interested in an application of Le Chatelier's principle, where an increase in pressure could result in a decrease in the moles of gas.
In particular, a situation where when the pressure ...
6
votes
0
answers
775
views
How can copper(II) sulfate crystallize outside a glass vial?
I'm making copper sulfate crystals in glasses. Within a few weeks, the copper sulfate seems to crystallize both inside and outside the glass:
(A few weeks after making a new solution)
(Yet another ...
5
votes
0
answers
187
views
What pH value of 1M sodium crotonate solution supposed to be?
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ ...
5
votes
0
answers
793
views
Solubility of PbSO4
The solubility of $\ce{PbSO4(s)}$ increase with the addition of $\ce{H2SO4}.$ Why?
I don't quite understand this. When dissolving $\ce{PbSO4(s)}$ we get the equilibrium equation:
$$\ce{PbSO4(s) <=...
5
votes
0
answers
479
views
Why does pKw first decrease but eventually increase when temperature rises?
I understand the initial decrease in pKw.
$\ce{Heat + H2O (l) <=> H+ (aq) + OH- (aq)}$
Temperature increases, reaction shifts to the right, so
$\ce{H+} \text{ and } \ce{OH}$ ...
5
votes
0
answers
98
views
Equations Used in Isothermal Titration Calorimetry
I have been attempting to understand and derive the formulas used for ITC which can be found here starting on page 310. I am particularly interested in the single set of identical sites. To first ...
5
votes
0
answers
159
views
Where is my antimony going?
I work in a trace metals laboratory operating an ICP-OES. I've been having some trouble with the recovery of antimony in a weak $\ce{HCl}$ solution post-digestion.
The antimony is part of a mix of ...
5
votes
0
answers
5k
views
Should I round an experimentally determined reaction order to an integer?
For a lab experiment I did, I calculated the reaction order for one of the reactants using data from two trials, both rates, and the concentration of that reactant during each.
$$
\frac{\text{Rate}_1}{...
5
votes
1
answer
553
views
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 ...
4
votes
1
answer
234
views
How does a silver chloride electrode (Ag/AgCl) convert the potential in aqueous solution to the wire?
I am aware of the redox chemistry that happens at the electrode surface, but I'm not sure how exactly a change in electrical potential in the solution would change the potential in the electrode?
4
votes
0
answers
86
views
Notation for spectral density in experimental community
In an open quantum system setup where the system is coupled to infinite harmonic oscillators as bath (as in the Caldeira leggett model, for example), through the Hamiltonian,
$$H = \frac{\hat{p}^2}{2m}...
4
votes
1
answer
366
views
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 $\ce{BaSO4}$, ...