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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Why do some solid chemicals dissolve better in colder water?

I just discovered that some solid chemicals, such as $\ce{Na2SO4}$, dissolve better in cold water than hot water from here and would like to know if there is any particular reason as to why. Is it ...
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Byproducts of the neutralisation of hydrochloric acid with sodium hydroxide

Given a 1 M concentration of $\ce{HCl}$ and $\ce{NaOH}$ here are the pHs: pH of $\ce{HCl}$: 1 pH of $\ce{NaOH}$: 13–14 and of course water has a pH of 7. Here is a reaction that is most likely to ...
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251 views

If volatility depends on intermolecular forces, then why in Raoult's law, two substances have different volatility?

I have a doubt, Ideal solutions are solutions where intermolecular forces between solute-solute and solvent-solvent are nearly equal to solute-solvent. Since intermolecular forces between A-A = B-B, ...
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639 views

Is there a soluble salt, or compound that when dissolved in water results in a solution with density less than pure water?

Generally water soluble salts tend to 'fit between' the molecules of water such that the volume of the resulting solution does not increase much relative to the volume and added mass of the salt. So ...
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503 views

Can a solid and liquid be miscible?

To be specific, what I mean is: is the following situation possible? At given temperature T, there are two substances, X and Y, such that pure X is a solid, pure Y is a liquid, and X and Y mix to form ...
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418 views

Is there a paper glue that is NOT dissolved by acetone?

Short version of the question: I need a spray-on glue that will stick paper to wood that isn't dissolved by acetone. Long version: I am trying to glue paper on wood. It's a big sheet of paper and I ...
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Dissolving Tylenol Science Experiment - why is it fastest in distilled water?

My son has a science experiment for class to dissolve Tylenol (325mg acetaminophen) in 3 different solutions (125 mL volume each): Distilled water Vinegar (1 part white vinegar to 4 parts water) Salt ...
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Is the density of the solution significantly different from the density of the solvent?

I am working on a mathematical model for the dissolution of coffee in water. I need to know some precise details about the effects of dissolution on the density of the mixture of the substances (that ...
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289 views

The partition coefficient for a chemical species across a membrane

What factors influence the partition factors across a membrane for a chemical species? Wikipedia defines the partition coefficient as: In the physical sciences, a partition-coefficient (P) or ...
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72 views

Dissolving to Create a Solution with Ethanol

If at 95% Ethanol can dissolve chemical X at 1mg/1mL then theoretically if you have 500mg of chemical X you can dissolve it in 500mL of $\ce{EtOH}$ to get 1mg/mL correct? My question is, if you have ...
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316 views

Standard solution and extracted solution : same concentration?

Summary : I am currently testing how a certain type of foam adsorbs HAP, PCB and OCP, and to this end I am depositing some on the foam, then extracting it. To know how much was extracted, I need to ...
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158 views

How to estimate HCN content in a volatile mixture?

How can you accurately qualitatively and quantitatively determine the HCN in a volatile product from water?
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255 views

Why droplets of water and ethyl alcohol solution freeze weirdly? [closed]

I'm doing a project where I freeze water drops and solutions with water and ethyl alcohol. It's a phenomena where drops create a conical shape at the end of their freezing. But with ethyl drops, with ...
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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 ...
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59 views

Reference request for the number of solvents around a solute [closed]

I want to know if there is a way to find number of solvent molecules that are directly embracing a solute molecule (something like a reference or table that shows waters of hydration). Particularly I ...
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269 views

Is it possible for an acid and base to react to form an even stronger base or acid?

Is there a combination of an acid and a base that when mixed results in a solution that is more basic or more acidic than the initial base or acid, respectively? If so, do such combinations have a ...
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Deviation from Raoult's law because of adhesive and cohesive forces

A solution made of two or more compounds have adhesive and cohesive forces. Cohesive forces are the attractive forces between the same molecules. Adhesive forces are the attractive forces between ...
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229 views

Finding sulfate contamination in crystallized silver nitrate

What is the best way to check for a small amount of sulfate contamination (if any) in silver nitrate? Usually, I would use dilute barium chloride to precipitate out the resulting insoluble white ...
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Does rate of Evaporation change with surface area?

Two vessels of the same volume, in the same location and open to the atmosphere. One is of a small diameter, the other is of a larger diameter. The question is will the vessel with the larger surface ...
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CuCl2 dissolved in water

We dissolve $10\ \mathrm{g}$ of $\ce{CuCl2}$ in $0.1\ \mathrm{L}$ of water. Given that: $M(\ce{Cl})=35.5\ \mathrm{g/mol}$ $M(\ce{Cu})=63.5\ \mathrm{g/mol}$ How can one calculate the molar ...
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Can Ice Packs Freeze Water at 21 °C?

I receive $120~\mathrm{mL}$ bags of medicine in sterile water. The medicine is refrigerated and then packed with a significant amount of ice packs in an insulated bag. Generally three times the volume ...
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3answers
293 views

Dynamic equilibrium in unsaturated solutions

One standard definition of equilibrium in beginner chemistry is that for a reversible reaction, (dynamic) equilibrium has been achieved when the rate of the forward and backward reactions are equal. ...
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713 views

How to determine if two calibration curves are parallel, within 5%

I have complex matrices and I need to make sure the matrix does not affect the measurement of my analyte. To do that, I need to prepare samples of my analyte in a solvent and of the matrix reinforced ...
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Why are solutions electrically neutral?

I keep reading that solutions are electrically neutral, but I've never read an explanation. I've read after the fact justifications, such as one problem which asked me to calculate the force of ...
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646 views

Mathematical explanation of blank titration in Mohr method for argentometry

In my book it is written that in order to minimize systematic error in Mohr method for argentometry it is a common procedure to conduct a blank titration with $ \mathrm{Ag^+} $ against a $\mathrm{CrO_{...
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343 views

Would ionic compounds dissolve in methanol?

Question: Determine whether liquid hexane ($\ce{C6H14}$) or liquid methanol ($\ce{CH3OH}$) is the more appropriate solvent for the substances grease ($\ce{C20H42}$) and potassium iodide ($\ce{KI}$)....
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535 views

Any other Colligative properties?

Are there any other colligative properties other than lowering of vapor pressure, osmotic pressure, boiling point elevation, and freezing point depression? I was wondering whether surface tension of ...
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86 views

If some particles of liquid in a solution convert to vapour then why can't some liquid particles convert to solid?

I was reading about the vaporisation of liquid when I came across the following statement. The average energy of the particles in a liquid is governed by the temperature. The higher the ...
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How to make a CCl3F Fluorine NMR standard?

I am running some fluorine NMR and would like to make a bulk solution of $\ce{CCl3F}$ in $\ce{CDCl3}$ to aid in assessing the amount of fluorinated product present by having my NMR solvent act as a ...
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Is there a way to dissolve glue?

Background: I have a journal from my childhood. I applied glue (uhu brand. this one) to the papers almost 10 years ago. Q: Is there a way to dissolve the glue and make the pages readable?
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340 views

Why does the conductivity of a LiOH solution decrease when boric acid is added?

If I start with pure water and add $\ce{LiOH}$ the conductivity of solution increases. However, if I then dissolve boric acid in the same solution the conductivity falls. I would have thought adding ...
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How to calculate the amount of substance of sodium that are in 10 mL of 30% sodium chloride?

How much of sodium is there in 10 mL of 30% sodium chloride? $30\%$ of $\ce{10 ml}$ is $\pu{3 g}$ $\ce{NaCl}$. There is $\pu{3000 mg}$ of $\ce{NaCl}$ and would that be divided by the molecular weight ...
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118 views

How soluble is uranium in molten iron?

As I know, uranium and iron simply aren't mixable, which means there are no U-Fe alloys. The Google says, uranium is insoluble in molten iron. But, if something is "insoluble", it actually means only ...
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Is lithium bicarbonate an aqueous solution of lithium carbonate?

This question is related to: Are Lithium bicarbonate and​ Magnesium bicarbonate both soluble in water? What type of chemical reaction is this? How can bromine water be called a solution? In the ...
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How to calculate the mass of water to add to copper(II) sulfate to form a 4% solution?

How many grams of water are required to make a $4.00\%$ solution with $15.0~\mathrm{g}$ of copper(II) sulfate pentahydrate? I calculated the percent composition of water in a molecule of $\ce{CuSO4....
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Why do exothermic dissolution reactions occur?

I've always been taught that an exothermic dissolution means that the forming of solute-solvent bonds releases more energy than the energy consumed to break solute-solute bonds and solvent-solvent ...
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Solvated solids

I have a very basic question concerning solvation. If a solid (solute) was dissolved in a liquid (solvent), is the solute still in the solid state? or does it convert into another state of matter when ...
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How does a shock, such as the snap of the disk in a reusable hand warmer, trigger the re-crystalization of a supersaturated solution?

Reusable handwarmers are made of something dissolved nearly to its saturation point in hot water (Sodium Acetate in the case of HotSnapz) at a high temperature, and then cooled to a temperature at ...
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137 views

What is the proper way to prepare a solution aiming to minimize errors?

I am a undergraduate student in chemistry, and my university is very weak in teaching solution preparation. I need to prepare a 10 mg / L methylene blue solution and now the way I do is, using an ...
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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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881 views

How can I calculate the molar conductivity of a solution with multiple solutes?

I'm running an experiment mixing 2 different solutions, $\pu{5 mL}$ of $\pu{0.1 M}$ $\ce{NaCl}$ with $\pu{5 mL}$ of $\pu{0.1 M}$ $\ce{KCl}$. I am measuring the conductivity of the total solution in $\...
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119 views

Is it possible to create a solution with superoxide?

I am not a chemist, and somehow I cannot find any material on this topic, so I decided to ask here. I am looking to create a solution with a specified amount/concentration of superoxide ($\ce{O2^.-}$)...
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Difference between freezing point and melting point

I do not understand why for mixtures freezing point is lower than melting point. Are not the two representing the same equilibrium between solid and liquid which we are approaching from two different ...
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Why is partial pressure proportional to mole fraction in Henry's law?

According to Henry's law of partial pressure, partial pressure of a gas above a solution is directly proportional to the mole fraction of the gas in the solution. But my question is: If the mole ...
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383 views

Dilution terminology

For thing like 8× dilution, that would be like 1 ml of a solution and then 7 ml of something like water to dilute right? Would 50 ml solution and 50 ml water be a 2× dilution? I’m a bit unsure about ...
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why do we obtain a sigmoid curve in vapour pressure versus temperature graph

i have recently got a question in an assignment, which was somewhat like this what would be the shape of curve obtained in a graph between vapour pressure & temperature of a binary solution in ...
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How is the formula of mean activity coefficient derived?

The mean activity coefficient is defiend as follows: $$\gamma_\pm = (\gamma_+\gamma_-)^{1/2}.\tag{1}$$ If Debye-Hückel equation $$-\log\gamma_i = 0.5z_i^2\mu^{1/2}\tag{2}$$ is used, then the mean ...
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790 views

Why does coke foam up when I add it to (cold) black coffee (no sugar, no milk)? [closed]

Album of the different gifs detailing this situation: Album of coke-coffee related gifs I thought that the answer would be similar to the ice-cream float situation, but I don't see what in the coffee ...
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83 views

Solubility of oxygen in liquid hydrogen; is anything near 1:2 (molar ratio) possible?

In a question on another Stack Exchange site a proposal was forwarded to premix oxygen and hydrogen in the stoichiometric molar ratio of 1:2 to be used as rocket fuel, as opposed to the standard ...
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Reaction of iron(III) oxide with nitric acid [closed]

I'm currently working in a project in which I have to convert the iron oxides present in iron ore slime into ferric nitrate. Iron ore slime is which has the particle size of below $\pu{0.15 mm}$ is ...

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