Questions tagged [aqueous-solution]
For questions relating to compounds dissolved in water and resulting reactions and acid-base equilibria.
163
questions with no upvoted or accepted answers
11
votes
1answer
295 views
What might serve as an initial starting photocatalyst for this large water-splitting solar simulator?
Question: What might serve as an initial starting photocatalyst for this large water-splitting solar simulator? Surely there must have been some planned experiments!
The Gizmodo article Insane Light ...
6
votes
0answers
3k views
Is iron(III) carbonate stable in water?
I searched for this onsite already, and also found the following answer on Quora:
In aqueous environment, iron(III) is bound by water molecules and exists as $\ce{[Fe(H2O)6]^3+}$. Due to strong ...
5
votes
0answers
132 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 ...
4
votes
0answers
261 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) <=...
4
votes
0answers
135 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 ...
4
votes
0answers
173 views
Why does viscosity decrease when divalent cations are dissolved into aqueous solutions of sodium carboxymethylcellulose?
Sodium Carboxymethylcellulose (CMC/NaCMC/Aqualon) is a common product used in many instances for its unique properties, especially its ability to make solutions viscous. It is well known that the ...
4
votes
0answers
2k views
How to break down soap and detergents?
I am building a greywater harvesting system. It is a 3-stage system:
The 1st stage breaks down soap and detergents.
The 2nd stage filters the water.
The 3rd stage pumps water out of system.
What ...
3
votes
0answers
159 views
Number of moles of acidified potassium dichromate required to liberate 6 moles of iodine from an aqueous solution of iodate ions
I came across this question in a recent exam I had taken:
How many moles of acidified $\ce{K2Cr2O7}$ is required to liberate 6 moles of $\ce{I2}$ from an aqueous solution of $\ce{I-}$ ?
So this is ...
3
votes
0answers
60 views
The most convenient process to purify Oxalic Acid up to a high level of purity
I am set out to purify a batch of commercial oxalic acid with the aim in mind to end up with a highly pure product (starting from $\pu{4,000 ppm}$ total impurities and doing so with basic lab ...
3
votes
0answers
39 views
Molar ratios not leading to complete reaction in Schweizer's reagent production
In my home lab, I've reacted $\ce{Cu(OH)2}$ with aqueous ammonia to produce Schweizer's reagent. However, I'm surprised by the amount of ammonia required to react with this amount of $\ce{Cu(OH)2}$. ...
3
votes
0answers
65 views
Removing Tungsten Trioxide from Tungsten Electrode
I need a very sharp tungsten electrode, and I think radial electrochemical etching with sodium hydroxide is the way to go. The problem therein (I think) is that the etching will cause an oxide layer ...
3
votes
0answers
642 views
Calculating total volume mixing NaCl and water
I'm (as a non chemist) trying to calculate the the volume of a NaCl solution. The problem is that I know the volume of water prior to mixing in NaCl, but I want to know the volume of the solution ...
3
votes
0answers
116 views
Chemistry Behind TMOS Aerogel
I have found out how to make silica aerogel.
Currently, the solution that I need to create to make the gel requires tetramethyl orthosilicate or TMOS. Furthermore, the procedure requires me to make ...
3
votes
0answers
147 views
Hydrogen Peroxide Heat of Dilution
Based on some data here, I am getting the heat of dilution of 100% $\ce{H2O2}$ as approx. 1100 cal/mole.
That's about 4.6 kJ/mol if I did my math right.
Is this a correct value? Seems too low to ...
3
votes
2answers
287 views
Does the salinity in seawater affect the process of alkaline hydrolysis?
I am an architecture student doing a project on crematorium spaces. I am looking at resomation or alkaline hydrolysis as an alternative method of disposition of a body. From what I gather from ...
3
votes
0answers
100 views
Poor aqueous solubility of chloroazodin
Below is the structure of chloroazodin:
Why is chloroazodin poorly soluble in water? It has multiple amine and imine nitrogens, all of which appear to be available for hydrogen bonding, and thus it ...
3
votes
0answers
66 views
Can a brine water electrolysis be looped?
Electrolysis of brine yields hydrogen and chlorine gases and aqueous $\ce{NaOH}$. So is it possible to combine the gases to form $\ce{HCl}$ gas, and mix it back with the aqueous $\ce{NaOH}$, so it ...
3
votes
0answers
528 views
The Health Effects of Alkaline Ionized Water?
I came across alkaline ionized water as my aunts bought a system called Kangen Water from Enagic Inc. The water produced by this system is claimed to contain smaller water clusters (4-6 molecules) ...
2
votes
0answers
22 views
Isomerization of phosphorylated 2-imino-1,3-dioxalanes into phosphorylated cyclic carbamates
I found a patent dating back to the Soviet Union. The patent number is 256764, and the patent describes the synthesis of phosphorylated cyclic carbamates. Here is a section of the patent, followed by ...
2
votes
0answers
35 views
Which salts precipitate from a potassium/sodium chloride/sulfate solution?
This is not a homework question. I am not in any course of study. The following question arises from my personal curiosity. If 1 mole of sodium sulfate and 2 moles of potassium chloride are dissolved ...
2
votes
0answers
56 views
Effect of charge density on electrolysis of dilute sulphuric acid
I am told that if electrolysis of dilute sulfuric acid is performed under high charge density, then the following reaction takes place at anode instead of evolving oxygen:
$$\ce{2 HSO4- -> H2S2O8 +...
2
votes
0answers
39 views
Hydrochloric acid substitute in an Iron-gall ink solution
Recently I started experimenting with making my own ink to be used in fountain pens.
I was wondering if hydrochloric acid in an iron-gall ink is used to prevent sediment ONLY by lowering the pH of ...
2
votes
0answers
32 views
Competing half reactions in electrolysis of aqueous solution of sodium hydroxide
If you run a direct current using pure nickel electrodes through a solution of NaOH in distilled water, you will separate the water into hydrogen and oxygen.
Are there any other reactions that could ...
2
votes
3answers
133 views
Tap water pH adjustment using citric acid
I've lowered tap water pH from 7 to 6 using citric acid. After couple of hours pH raised again to 7.
What is the reason for this raise? Citric acid overcomes waters buffering feature then raise the $...
2
votes
0answers
46 views
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
votes
0answers
32 views
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
votes
0answers
57 views
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 ...
2
votes
0answers
23 views
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
votes
0answers
160 views
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 ...
2
votes
0answers
33 views
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 ...
2
votes
0answers
131 views
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 ...
2
votes
0answers
226 views
Varying data about solubility of sodium acetate trihydrate
I recently looked up the solubility of sodium acetate trihydrate in water at 20Ā°C and found surprisingly diverse values such as:
613g/l (GESTIS-Stoffdatenbank)
762g/l (TU Freiberg)
1250g/l (applichem, ...
2
votes
0answers
42 views
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 $\...
2
votes
0answers
297 views
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 ...
2
votes
0answers
58 views
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....
2
votes
0answers
66 views
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:
$$\...
2
votes
0answers
158 views
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 ...
2
votes
0answers
124 views
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 ...
2
votes
0answers
39 views
Extimating the repartition of water between hygroscopic compounds
Sulfuric acid is sometimes used as a drying agent.
According to literature, one possible application is, for instance, in the drying of bromine.
Some questions came to my mind: which concentration ...
2
votes
0answers
2k views
Why do fluoride ions “win” over thiocyanate ions in a solution with iron ions?
When you mix aqueous iron(III) nitrate and potassium thiocyanate together you get a red solution. Then if you add sodium fluoride, the red colour disappears.
This is basically because the $\ce{Fe(...
2
votes
0answers
653 views
How does increasing ionic strength affect the pH of solution?
I'm having trouble interpreting the data for an experiment. With increasing ionic strength, I found lower solubility but also lower pH of the solution. What is the effect of the ionic strength on the ...
2
votes
0answers
100 views
Chemical theory, formula(s) that predict final *volume* of a solution?
I asked this question a couple years back regarding the volume of a mixture being less than the volume of the original solute and solvent, but this question asks if there is theory and/or formulation ...
2
votes
0answers
41 views
Ionic emission spectrum contamination
Imagine that I am trying to identify the presence of ions from among the metals $\ce {Li,Na,K,Ca,Sr, Ba}$ in some solution through their emission spectrum.
By mistake the wire used to introduce ...
2
votes
0answers
111 views
Will bases typically precipitate silver atoms from silver ions?
In class I learnt that one can dissolve many substances using acid and that this can be predicted using standard electrode potentials. For example,
$$\begin{align}
\ce{Zn &-> Zn^{2+} + 2e^-} ...
2
votes
0answers
272 views
Why do some insoluble salts undergo slow chemical reaction instead of dissociation in water?
$$\ce{PbCl2 + H2O ->[\Delta] Pb(OH)Cl + HCl}\tag{1}$$
$$\ce{2ZnCO3 + H2O ->[\Delta] Zn2(OH)2CO3 + CO2}\tag{2}$$
$$\ce{2NiS + 2H2O ā Ni2(OH)2S + H2S}\tag{3}$$
$$\ce{Hg2SO4 + H2O ā HgO + Hg + ...
2
votes
0answers
41 views
Measuring the effect of increasing salinty on the concentration of Dissolved oxygen
I want to investigate the effect of increasing salinity on the concentration of dissolved oxygen, in a water sample being distilled water.
Would that work?
My concern is, that since its not a true ...
2
votes
0answers
356 views
Why is silver chromate red?
Copper(II) ions are blue and chromate(VI) ions are yellow therefore copper(II) chromate(VI) would turn out to be green because it's a mixture of blue and yellow.
In the same way, silver ions are ...
2
votes
0answers
84 views
Do filter-specific dyes exist? Equivalently, do dye-specific filters exist?
Apologies if this isn't chemistry enough for chemistry.se. I'm happy to go elsewhere if there are suggestions.
Blue + Red = Purple is arbitrary here. If any different colors might make this more ...
2
votes
0answers
387 views
Difference in color between the chromate and permanganate ions
As the title states, I'm wondering why the $\ce{[CrO4]^2-}$ and $\ce{[MnO4]-}$ ions display different colors in solution. Both of the metal ions have a $\mathrm{d}^0$ electron configuration, have the ...
2
votes
0answers
165 views
Alternative to water as solvent for lithium metaborate?
I want to prepare a sample of lithium metaborate ($\ce{LiBO2}$) and need to dissolve it for this purpose.
The only solvents I found so far are water and ethanol. In ethanol, one cannot dissolve ...
