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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7
votes
2answers
361 views

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 ...
5
votes
2answers
202 views

Is there a potentiometric method for monitoring salt formation in organic solvent?

I work in a pharmaceutical R+D lab, and currently aim to develop a validatable potentiometric method for determining the optimal amount of acid to add to a basified small organic molecule for ...
4
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0answers
68 views

Is there an adhesive that is not dissolved by acetone?

I am trying to glue glass sheets together to make a sealed 13" x 13" x 13" box. Inside this box there would be acetone gas used to melt 3D printed parts to make them more durable. Acetone will remove ...
4
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0answers
508 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 ...
4
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0answers
241 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
100 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
162 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?
4
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1answer
86 views

In the nonideal solution, why can't one of the solute be positive deviation and the other be negative deviation?

In the nonideal solution, why can't one of the solute be positive deviation and the other be negative deviation? Let's say A and B makes a nonideal solution. The moleculat force between A and B means ...
3
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0answers
35 views

Discussion about Warren-Cowely Parameter

The Warren-Cowely Parameter (WCP) for short range solution order is defined as: $$\mathrm{WCP}_{ij} = 1 - \frac{Z_{ij}}{x_j \cdot Z_i}$$ where $Z_{ij}$ is the partial Coordination Number (CN) of ...
3
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0answers
54 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
667 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
465 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 ...
3
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0answers
786 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
136 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
211 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 ...
3
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0answers
158 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 ...
3
votes
2answers
103 views

How can one reclaim isotopic cadmium from a solution of acid, i.e. H2SO4 or HCl etc.?

I have dissolved isotopic cadmium-114 with $\ce{H2SO4}$ and or $\ce{HCl}$. Now that I have the cadmium-114 in solution, precipitating out $\ce{CdSO4}$ and or $\ce{CdCl2}$, how can I reduce these ...
2
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0answers
26 views

Colligative properties: why does the size of solute not matter?

Colligative properties are defined as the "properties of solutions that depend on the ratio of the number of solute particles to the number of solvent molecules in a solution, and not on the ...
2
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0answers
59 views

Understanding formulas for PZT

In the slides i'm studying (about the production of PZT), is given the following formula for lead zirconate titanate : $$\ce{PbZr(Ti)O_3}$$ with the explanation: It is a solid solution of two oxides: ...
2
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1answer
58 views

Creating a chemical solution with water and chlorine

I bought a swimming pool for my kids and also a measurement instrument for measuring the amount of chlorid in the pool in mg/l. The problem is now that you have to calibrate the instrument before ...
2
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0answers
24 views

Is the total ionic-dipole bond (hydrogen bonds) acting on an ion stronger than the lattice energy holding the ions together?

When magnesium chloride dissolves in water, its $\Delta H^⦵_\mathrm{sol}$ is negative. Since $\Delta H^⦵_\mathrm{sol} = \Delta H^⦵_\mathrm{hyd} - \Delta H^⦵_\mathrm{latt},$ this means $-\Delta H^⦵_\...
2
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0answers
40 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
1answer
604 views

Kohlrausch Law and conductivity

Im writing up a lab report at the minute and part of it concerns ions in solution and how they affect conductivity. I've been doing lots of reading and I think ive got the grasp of most of it, but its ...
2
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0answers
86 views

while using Henry's law does it matter if the solvent is volatile or not?

I am studying about binary solutions (with liquid solvents) and came across Henry's law. This is how it's stated in my textbook: Henry's law states that at a constant temperature the solubility of ...
2
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0answers
559 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 ...
2
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0answers
34 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
306 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
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0answers
60 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
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0answers
270 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
427 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, ...
2
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0answers
2k 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'...
2
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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
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0answers
594 views

Calculating the pH of buffer solution made of two salts of a polyprotic acid

When we are making a buffer solution by solutions of a weak acid and its salt like $\ce{CH3COOH}$ and $\ce{CH3COONa}$, or by a weak base and its salt like $\ce{NH3}$ and $\ce{NH4Cl}$, we can use the ...
2
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0answers
731 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
38 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?
2
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0answers
843 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) $\ce{C6H12O6}$ (...
2
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0answers
65 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
736 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{...
2
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0answers
28 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 ...
2
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0answers
55 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 ...
2
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0answers
128 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
58 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
72 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, ...
2
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0answers
97 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 ...
2
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0answers
290 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 ...
1
vote
1answer
76 views

In what solvents does ionic association occur?

When a ionic compound like $\ce{NaCl}$ dissolves, it doesn't always full dissociate due to ionic pairing. This is measured by the van 't Hoff factor. Now, this is what I'm looking at for my chem ...
1
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0answers
57 views

Freezing point of solution of Water, Ethanol and Sugar (aka, Limoncello)

I'm looking for a diagram of the freezing point of a water solution depending on its content in sugar and ethanol. More colloquially, I want to know how to balance alcohol and sugar so that my ...
1
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0answers
28 views

What is vacuum-assisted ultrasonication?

This quote from a methods section of a paper: [samples were] ultrasonicated for approximately 30 min to ensure adequate dispersion of the components throughout the mixture. The solution was then ...
1
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0answers
27 views

Column Dispersive Mass Balance analytical / numerical solution

Is there any analytical solution for the most common expression of column mass balance: $\dfrac{\partial C}{\partial t} + \left(\dfrac{1+\varepsilon}{\varepsilon}\right)\dfrac{\partial q} {\partial t} ...
1
vote
1answer
45 views

Confusion on when to use mass of entire solution when performing q=mc∆T

I hope you are having a good day. I am studying for the AP Chemistry exam in May 2020. While studying, I encountered a doubt. In Problem 1 (the question on the top), the educator saw that the ...