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Questions tagged [solutions]

This tag should be applied to questions dealing with solutions of any kind. A solution is a liquid or solid phase containing more than one substance where, for convenience, one (or more) substance(s) called the solvent is treated differently from the other substances, which are called solutes. If water is the solvent, then the more appropriate 'aqueous-solution' tag should (also) be specified.

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Apparent contradiction in the type of deviation of an ethanol-water mixture

For a mixture of $\ce{EtOH}$ and $\ce{H2O}$: $\Delta H_{\text{mix}} < 0$ (exothermic) and $\Delta V_{\text{mix}} < 0$ (volume contraction). This means that the unlike interactions are stronger ...
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411 views

Theory of volume contraction in solution

When a solid is dissolved into a liquid, or two solids are amalgamated, their mutual volume will contract. For example, a crystal of sugar having a volume of one cubic inch dissolved into 10 cubic ...
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179 views

Do extreme homeopathic dilutions still retain quantities of the starting materials?

This Indian Institute of Technology Bombay press release quotes some research papers which claims to prove that homeopathic remedies do retain original substances even when diluted. The paper ...
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176 views

Debye-Huckel theory with non-polar solvents

I want to calculate the activity coefficients of mixed solvent salt solutions. I am seeing very strange behavior when I try calculating the activity coefficient of salts in non-polar solvents using ...
4
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0answers
96 views

Synthesizing monodisperse PbS quantum dots

For a research project, I am trying to synthesize lead (II) sulfide quantum dots using the method of Li et al.. I am injecting sulfur dissolved in 1-octadecene into a mixture of $\ce{PbO}$, oleic ...
4
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0answers
158 views

How do xanthan gum and other hydrocolloids work?

Does anyone know what causes things like xanthan gum to make water into a slimy substance on the molecular level?
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0answers
48 views

Phantom Material: why formaldehyde doesn't rise my jelly melting point?

Just to be clear, I'm not a chemical but only a electronic engineer which want create a "phantom material" to reproduce the electrical characteristic of epidermis for the analysis of electrodes ...
3
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0answers
17 views

Is there a concise notation for a solution of one substance in another?

I'm aware of phase notation of $\ce{(aq)}$ for aqueous solutions. Is there something similar for solutions of chemical X dissolved in chemical Y?
3
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0answers
321 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
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0answers
104 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
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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
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0answers
942 views

Calculating the Activity Coefficient parameters form Henry's Law

Here is the question, I am stuck on part B: Basically, this is my thought process so far, as $x_a \rightarrow 0$, the Henry's law line becomes tangential to the actual partial pressure curve.. Henry'...
3
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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
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0answers
477 views

how was freezing point depression dependence on solute concentration described?

Molarity is arguably the most intuitive descriptor for the "number of particles". But freezing point depression dependence on solute concentration is commonly described in textbooks as a function of ...
3
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0answers
287 views

Dissociation of H3PO4 and colligative properties

Which of the following solutions that have concentrations of $0.01\ \mathrm{M}$ show the highest elevation in boiling point and why? A) $\ce{NaCl}$ B) $\ce{CaCl2}$ C) $\ce{H3PO4 }$ D) $\ce{...
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0answers
85 views

Why are critical micelle concentrations so large?

Dissolving a non-polar molecule in water incurs a free energy cost of about $10 kJ/(mol \cdot nm^2)$ (source: http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=101826) The entropy gained from ...
3
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0answers
51 views

Behaviour of oleophobic and hydrophobic object in an oil and water solution

I am wondering what would happen if I put a small (between $\mathrm{5mm}$ and $\mathrm{1\mu}$, density between $\mathrm{1}$ and $\mathrm{2\: g/mL}$) item with both oleophobic and hydrophobic ...
3
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0answers
126 views

How to prevent Tin ions from precipitating as Tin(II,IV) Hydroxides

Alright, so Tin ions in most of it's salts have the propensity to form Tin(II,IV) Hydroxides and then precipitating out of aqueous solutions. What can I throw in the solutions to prevent this? Using ...
2
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0answers
46 views

Why does LDA solution gradually turn dark brown?

LDA (lithium diisopropylamide) solution in THF/hexane gradually turns red-brown liquid. Especially commercially available one is extremely dark red-brown. What makes it brown? I've searched online ...
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32 views

QM modelling of charge separation reactions

I have a general question regarding the modelling of reactions in which neutral reactants form charged species/ions (in solution). How can one get the energetics approximately right on reactions like ...
2
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0answers
149 views

Heat and Sugar Syrup Consistency

I make my own sugar syrups and have been observing how heating the syrup to different degrees results in syrups of radically different consistencies, I wonder why. Heating up syrups (4:3 Sugar:Water) ...
2
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0answers
247 views

What solution is not in equilibrium?

An example of a solution not in equilibrium (A) Chemical ph indicator (B) Acid/base buffer (C) Anhydrous solution (D) hypotonic solution (E) Supersaturated solution I eliminated A and ...
2
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0answers
364 views

Homemade copper etching solution

I'm trying to make an etching solution for copper (PCB) with easy to access materials. I'm using hydrochloric acid (9%), peroxide (common "oxygene" that contains many more ingredients), table vinegar, ...
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489 views

Copper sulphate solution dissolves iron nail?

I tried an experiment of the Galvanic series and put three iron nails (slightly rusty, but brushed) into a copper sulphate solution and waited a few days until the nails get coated with copper. ...
2
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0answers
35 views

Does isopropyl alcohol have a similar affect as dipropylene glycol regarding absorption?

I am an aromatherapist and am making essential oil reed diffusers. Do you know if isopropyl alcohol has a similar affect in absorption as dipropylene glycol?
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0answers
52 views

Looking for solubility kinetics of zinc chloride hydroxide monohydrate

$\ce{Zn5(OH)8Cl2.H2O}$ is a crystalline solid insoluble in water. Often used as nutritional supplement. Preparation and chemistry of zinc chloride hydroxide monohydrate is known. I am looking for some ...
2
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0answers
118 views

How many mL of 10.00 M HCl are needed to make up 80.0 mL of 0.175 M HCl?

I've tried this multiple times, but I don't know how to set the problem up when it gives you both molarities. If someone could show me how to set up this problem please!? I think it has something to ...
2
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0answers
424 views

Does complex formation lead to increase in freezing point?

Original question:- When mercuric iodide is added to an aqueous solution of Potassium iodide, freezing point increases. Why? Answer given:- Due to formation of Complex $\ce{...
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0answers
24 views

Solvation rates of crystalline and noncrystalline materials

Assuming equal surface area (and other variables), would a highly ordered crystal of some substance dissolve more slowly or quickly than (or at the same rate as) a disordered sample of the same ...
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0answers
1k views

How to determine the empirical formula given mass percentages of the elements and the molecular weight?

A compound has $67.3 \% \rm~C,4.62 \%~N,6.93 \%~ H$ and O. Determine the molecular formula of the compound knowing its molar mass is $283\rm~\frac{g}{mol}$. My solution : The percentage for the ...
2
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0answers
98 views

Methods of dissolving a gas into a liquid

I know that carbon dioxide is dissolved into water in a soda fountain using a sort of a tubular manifold that mixes the water with pressurized carbon dioxide as it goes through it. Is that the best ...
2
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0answers
56 views

Method for increasing concentration of extracts

I am using reagent grade propylene glycol (99.9% pure) and vegetable glycerin (99.7% pure) separately as solvents to extract certain active essential oils/molecules of various plant flowers. The ...
2
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0answers
70 views

If a conductivity meter is calibrated with aqueous standards, can it be used to measure the conductivity of an organic-based solvent system?

Trying to figure out if the calibration solutions for a conductivity probe/meter must be of a similar nature to the system which will be measured. I can only find aqueous calibration solutions online, ...
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76 views

Ink / formulation chemistry: What lab requirements

Little open information can be found on the requirements of the manufacture, development and testing of gel and printing inks. It seems that most ink manufacturers have their own specific lab ...
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0answers
269 views

How to derive the energy of solvation equation?

The work done as a ion is solvated is given by: $-z^2e^2/8\pi\epsilon r$ but since the top line can be written $Q^2$, for simplicity I will say the equation is $-Q^2/8\pi\epsilon r$. Is this derived ...
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0answers
31 views

Is awaruite to nickel sulfate possible?

Much time has passed since my basic chemistry and I am trying to determine if an awaruite mine proposed by FPX Nickel Corp ("FPX") might serve as feed-stock to nickel sulfate for battery production. ...
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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. ...
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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 ...
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0answers
32 views

Hypothetically, can sufficiently powerful centrifugation separate normally miscible chemicals of differing densities?

Centrifugation is used to separate phases in suspensions by density. I read that this is not possible with colloids and solutions, but the distinction between the three seems to be optical properties ...
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0answers
51 views

What's the density of a frozen ethanol or ethanol solutions?

How can we know what's the density of ice (water), but there's no data on how much is the density of frozen ethanol? (as far as I know)
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0answers
101 views

How does the molarity of a solution change on boiling off the solvent?

The dilution equation $$M_1V_2=M_2V_2$$ is an equation that can be used to calculate how adding water can impact the volume and molarity of a solution. So I was wondering if this equation would apply ...
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0answers
22 views

Can the solutions for the Briggs Rauscher experiment be made ahead of time and stored?

I will be performing the Briggs Rauscher Oscillating reaction as a part of an investigation into the effect of heat on the antioxidants. This will require 3 solutions to be mixed together, as shown ...
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0answers
65 views

Kinetics of A + 2 B -> C reaction

A reaction $\ce{A + 2 B -> C}$ is carried out in constant volume at $\pu{227 ^\circ C}$. the volume is $\pu{2 L}$. There is no $\ce{C}$ at the beginning. $[\ce{A}]_0 = \pu{0.035 mol L-1}$. $\ce{B}$ ...
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0answers
280 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 ...
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0answers
1k views

Why do chloroform and benzene exhibit negative deviation from Raoult's law?

Chloroform is a polar molecule, and benzene is nonpolar. Shouldn't the chloroform-chloroform and benzene-benzene intermolecular forces be stronger than chloroform-benzene interactions (like dissolves ...
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0answers
35 views

How can it be determined that a liquid is saturated with a gas?

How can it be determined if a liquid is saturated with a gas? For example, if I am introducing carbon dioxide to water at 40 PSI at 35F in a sealed container, how would I know at what point the water ...
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0answers
22 views

Determining pH of immunoprecipitation buffer recipe

I'm following a protocol for extraction of proteins from yeast, and I came across this recipe for immunoprecipitation buffer: $\pu{50 mM}$ HEPES-$\ce{KOH}$, pH 6.8, $\pu{150 mM}$ $\ce{KOAc}$, $\pu{...
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0answers
51 views

SO3(2-) to Na2S2O5 ratio

Is there a way of calculating the amount of sodium metabisulfite from the sulfite content? I found online instructions for the test kit for sulfite that suggests multiplying by $2.37$ to obtain $\pu{...
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0answers
82 views

How to interpret the shape in this representation of an electride?

This excellent answer describes the appearance of solvated electrons in ammonia as first a blue, and then metallic color. It is produced by dissolving sodium in ammonia at low temperature. According ...
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357 views

Predicting the vapor pressure of water ammonia solution

I am working on a project that involves the compressors for a vapor compression refrigeration cycle of R717 (ammonia) and came across something that has been boggling my mind a little bit for no good ...