Unanswered Questions
241 questions with no upvoted or accepted answers
2
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What is the pH and pKa relationship of LaCl3 in water and its precipitant La(OH)3?
In light of this question and its answers, I hope to get some insights into the $\mathrm{pH}$ of $\ce{LaCl3}$ in water and its $\mathrm{pH}$ relationship to $\ce{La(OH)3}$ precipitant's $\mathrm{p}K_\...
- 44.3k
2
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65
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Do I understand correctly that simulation volume influences relative permittivity calculations? If so, how is the result useful?
I am having a lot of trouble understanding the influence of volume on relative permittivity/static dielectric constant. I'm not a chemist, but am using molecular dynamics to calculate relative ...
- 2,242
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Activity of NaCl aqueous solution at high ionic strengths: Common-ion effect
Is there any theoretical way to estimate the activity of $\ce{NaCl}$ at high ionic strengths in water and that in $\pu{7 M}$ $\ce{NaCl}$ solution? This question is based on whether solubility of $\ce{...
2
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81
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Is it appropriate to approximate solute particles in a dilute solution as an ideal gas?
I was studying osmosis and I came across the formula for osmotic pressure. I decided to see the derivation for osmotic pressure in a dilute solution. The derivation involved an equation involving the ...
- 22.5k
2
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Cleaning a stubborn Electrospray residue
I have an electrospray ionization capillary tip that sprays into a chamber that contains some circuit boards. An aqueous CsI sample is apparently causing a white residue to build up on these boards ...
2
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260
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Mechanism for removal of pesticides from fruit by sodium bicarbonate
When Googling around for methods to remove pesticides from fruits and vegetables, a study commonly referred to from some news sites (e.g. here and here ) is one where soaking apples in a sodium ...
- 29
2
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Non-hydrate forming salts?
Are there any water-soluble salts that don't form hydrates?
Hydration seems very thermodynamically favorable, as evidenced by its abundance. It also makes sense since the solvation and hydration ...
- 1,690
2
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Why is fluoride good for your teeth?
The main component of tooth enamel is calcium hydroxyapatite. I know fluoride ions can replace hydroxide ions in the enamel matrix, slowing the rate of enamel demineralization. Why does hydrofluoric ...
- 79
2
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298
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Varying data about solubility of sodium acetate trihydrate
I recently looked up the solubility of sodium acetate trihydrate in water at 20°C and found surprisingly diverse values such as:
613g/l (GESTIS-Stoffdatenbank)
762g/l (TU Freiberg)
1250g/l (applichem, ...
- 346
2
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48
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Should the concentrations in weight % of the components of a solution always add up to 100%?
There's a paper with this statement of a alkaline solution:
Nanostructured CuO films were formed by immersing the cleaned tabs into a hot $(\pu{96 \pm 3 ^\circ C})$ alkaline solution composed of $\...
- 29
2
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406
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What determines the maximum size of salt crystals as grown in flux growth?
Like many other children, I grew single crystal salt crystals in a salt solution. This is a common and fun experiment for children.
However, with both this experiment, and with flux growth methods ...
- 276
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90
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Why does soapy dishwater lose soapiness over time?
I wash dishes by making a concentrated solution of dishsoap (eg dawn) and water. Sometimes I'm lazy and forget to wash the container containing the soap solution, and it sits on the counter overnight....
- 17.6k
2
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75
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How fast does atmospheric carbon dioxide dissolve into strongly basic solution?
I'm conducting some pH measurements with solutions containing NaOH and I'm a bit concerned that carbon dioxide will dissolve and affect my measurements by lowering the pH according to the reaction:
$$\...
- 397
2
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203
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Narrow range of pH for the formation of polyoxometalate clusters
The molybdate ion in aqueous solutions, speciates as clusters known as polyoxometalates (POMs) when it is acidified, but these clusters only aggregate in a very narrow pH range "polymeric range" in ...
- 4,606
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207
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Vacuum filtration: will Polymer elements interfere with the vacuum?
I am doing an experiment with vacuum filtration, where a Nylon filter is used to create a membrane (marked in pink in the picture attached). When I use the membrane, it frequently breaks in the ...
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