Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [aqueous-solution]

For questions relating to compounds dissolved in water and resulting reactions.

5
votes
0answers
100 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
95 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
113 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
385 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) ...
4
votes
0answers
1k 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
1k views

Why does saline have a pH of 5.5?

I am a physician and administer 0.9% NaCl in water ("normal saline") to patients frequently. The bag says it has a pH of 5.5 (compared to the human body of 7.4). I am asking why the pH is so low. It ...
3
votes
0answers
28 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
323 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
105 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 ...
3
votes
0answers
47 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....
3
votes
0answers
85 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
838 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(...
3
votes
0answers
81 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
0answers
38 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 ...
3
votes
0answers
86 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
38 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
24 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
126 views

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, ...
2
votes
0answers
245 views

Solubility of Calcium Oxalate in Aqueous Alcohol?

In searching through the literature for the solubility of calcium oxalate, I came across this post https://www.researchgate.net/post/Are_there_any_organic_inorganic_solvents_for_dissolving_Ca-oxalate ...
2
votes
0answers
39 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
2k views

Best way to dissolve/emulsify beeswax and carnauba wax in water-based solution

What I can use to dissolve beeswax and carnauba wax and keep it in an aqueous solution? I do not want to use ethanol or acetone as they are too harsh. I am adding about $\pu{5\%}$ wax to a $\pu{16oz}$...
2
votes
0answers
56 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
119 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
70 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
32 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
452 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
74 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
2k views

How to make a buffered 10% formalin solution

How can you prepare a solution of 50 mL buffered 10% formalin using the following reagents? 100% formalin (100 mL) Phosphate buffer (100 mL) I know I can mix 5 mL of formalin and 45 mL of distilled ...
2
votes
0answers
437 views

Precipitation of citric acid by CaCl2 and Ca(OH)2?

I need to precipitate citric acid from an aqueous solution in the form of calcium citrate. There are, to my knowledge, two different methods of doing this: using $\ce{CaCl2}$ and which will react ...
2
votes
0answers
89 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
181 views

Why do some insoluble salts undergo slow chemical reaction instead of dissociation in water?

$$\ce{PbCl2 + H2O ->[\Delta] Pb(OH)Cl + HCl}\tag{1}$$ $$\ce{2ZnCO3 + H2O ->[\Delta] Zn2(OH)2CO3 + CO2}\tag{2}$$ $$\ce{2NiS + 2H2O → Ni2(OH)2S + H2S}\tag{3}$$ $$\ce{Hg2SO4 + H2O → HgO + Hg + ...
2
votes
0answers
247 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
82 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
238 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
32 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 ...
2
votes
0answers
138 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 ...
2
votes
0answers
144 views

If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium?

If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium? Can the same argument be applied to nitrous acid and nitrite ion in ...
2
votes
0answers
58 views

Preparing CdSe electrodeposition bath

What is the best way of preparing an aqueous solution containing 5 mM $\ce{CdSO4}$, 1 mM $\ce{SeO2}$, 0.5 M $\ce{Na2SO4}$ and adjusting pH to 3 by adding 0.5 M $\ce{H2SO4}$? What is the ...
2
votes
0answers
93 views

Isoelectric point pH, mV, for a metal oxide nanopowder

I'm trying to make a solution of $\ce{TiO2}$ that will coat stuff in as dense a monolayer as possible. To do so, I'm using nano sized $\ce{TiO}$ particles and trying to get them to get as close to ...
2
votes
0answers
108 views

Maintaining a 40% CO₂ aqueous environment?

I wish to grow algae in a 40% $\ce{CO2}$ (water under air with 40% $\ce{CO2}$ content) aqueous environment. Simple DIY methods are available, but they are generally unreliable (For more info on DIY ...
1
vote
0answers
24 views

How to make rheoscopic fluid using glycol stearate flakes

Rheoscopic fluid can be made by adding mica powder to water. I read that mica powder can settle and condense after sitting around for a long time. So I want to use glycol stearate flakes instead. ...
1
vote
0answers
16 views

Dependence of Osmotic Effects on Particle Size

van't Hof's equation for osmotic pressure is derived with the assumption, among others, that the particle size of the solute is comparable to the particles size of the solvent. It holds well so long ...
1
vote
0answers
54 views

Formulation of a suspension of Magnesium Hydroxide

For a school project of mine, I have to formulate a suspension of Magnesium Hydroxide which contains at least 50% of solid matter. This suspension is prepared from Magnesium Oxide 98% with a ...
1
vote
0answers
99 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 ...
1
vote
0answers
51 views

Can a molecular sieve be used increase the saturation of a fructose solution?

The Problem: Let's say we have an experiment where we are attempting to grow rock candy crystals by letting a solution of sugar crystalize on a wooden dowel. However, an error may have been made in ...
1
vote
0answers
15 views

Acid/base separation in nanofiltration

How do semi-permiable membranes handle salts that can separate into an acid and a base based on the "rules" of the membrane? For example, say I have a nanofiltration membrane that rejects ...
1
vote
0answers
33 views

Conductivity variation on Caustic (NaOH) Dilution System

I am reading the drawing for an automatic caustic dilution system where 50% NaOH is diluted down to 20%. I was expecting to see a density sensor on the outlet to provide feedback to the dilution ...
1
vote
0answers
25 views

Potentiometric determination of fluoride

We did an experiment of potentiometric determination of fluoride ions. In several beakers we added several concentrations of NaF solutions and then we added water. We calculated with the electrode the ...
1
vote
0answers
281 views

Is the crystallization process of aqueous solutions of substances such as lithium chloride endothermic?

$\ce{LiCl}$ has an enthalpy of solution of $\pu{-37.1 kJ/mol}$, so its dissolution process is exothermic. Does this mean that it's crystallization process is exothermic? I'm asking since I've looked ...
1
vote
0answers
33 views

Charge Balance and power law?

I've come across a statement in a paper* that's poorly explained, and I can't work out the reasoning behind it. I suspect this is embarrassingly basic, but could anyone please explain the theory ...