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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24 views

Ion Flux in nerve cells

Cell membranes separate intracellular and extracellular space, and the membrane is permeable to certain ions depending on the excitation of the nerve cell. The extracellular space contains many ...
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What is the ∆H_vap when temperature of a given liquid is equal to the boiling point of the liquid?

What is the $∆H_{vap}$ when temperature of a given liquid is equal to the boiling point of the liquid? For the other cases ie (i) T>BP, $∆H_{vap}$ > 0 (ii) T<BP, $∆H_{vap}$ < 0 So what ...
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1answer
53 views

Mixing hydrogen peroxide and sodium hydroxide doesn't lead to sodium peroxide anymore [closed]

I've been using same bottle of hydrogen peroxide and same bottle of 50 % of sodium hydroxide to make sodium peroxide for a month now. You could see the presence of sodium peroxide in the solution ...
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1answer
16 views

Osmolality and osmolarity of infant formula

Actually, this question is about the following sentence, which I have seen (in various forms) in numerous papers (e.g. this one and this one): The American Academy of Pediatrics advises that formulas ...
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1answer
34 views

How does addition of side chains affect solubility and processibility of polyphenylene vinylene?

I am studying electrical engineering and physics. In a recent lecture I was told the $\ce{OC1C10}\text{-PPV}$ molecule has the chains added to the oxygen atom down below because it allows for ...
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23 views

Vapour pressure and boiling [duplicate]

I have come across two definitions for boiling point: It is the temperature at which a liquid gets vaporised It is the point where vapour pressure = external pressure How are they related? How does ...
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2answers
126 views

Peak in beer freezing temperature plot

I left an open beer in the freezer while monitoring its temperature. The first minutes works as expected. But after the plateau, at about −8 °C, a peak appeared: I thought it was an artefact because ...
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1answer
271 views

How much solvent do you add for a 1:20 dilution, and why is it called 1 to 20? [closed]

A 1:20 dilution implies that you take 1 part of stock solution and add 19 parts of water to get a total volume of diluted solution equal to 20 times that of the stock solution So is ...
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91 views

Why is there preferential adsorption of a common ion during preparation of colloids by peptization?

There was a similar question asked here on Chem SE, but the answer was not very satisfactory to me, so I am asking a fresh question. Peptization is the process of creating a colloid from a precipitate ...
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55 views

Why should hydrogen peroxide be added to sulfuric acid and not vice versa?

When preparing aqueous solutions of sulfuric acid through dilution of the pure acid, it is well known that we should add acid to water and never the reverse. To prepare a solution of hydrogen peroxide ...
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Why does pure alpha glucose powder clump when attempting to dissolve in water and become very hard?

I noticed that when I attempted to dissolve some pure alpha glucose powder in water, it would become hard and clump at the bottom of the beaker if I dumped it into the beaker all at once. It was ...
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1answer
38 views

Energy required to break apart water molecules in dissociation?

I'm learning about the process of dissociation. I'm aware in dissolution that essentially three processes occur (I know I may be simplifying it, but I am in Year 11): Solute particles break apart (...
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Can different components show different deviations from Raoult's law?

Introduction: Raoult's law is used to calculate the partial pressures of the vapour phases of volatile components of a solution Given that there are two components, A and B, in the liquid-liquid ...
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I have tried to remove oxidation from a metal scraper using vinegar, now the metal looks and smells burnt, what went wrong?

I have recently tried to remove some oxidation from a metal scraper spatula by using vinegar. After leaving it there for a couple of hours I was left with a burnt smell (with a hint of burnt candle ...
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1answer
73 views

Heating NaOH solutions

I am trying to determine the best heat at which to use an NaOH solution to clean a textile fiber. This is being done, carefully, in Asian villages. The raw material is ribbons of bark peeled from a ...
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61 views

Why does conductivity of a solution of sodium in liquid ammonia decrease with a decrease in temperature?

What happens to the conductivity when a solution of sodium in liquid ammonia at $\pu{-33^{\circ}C}$ (Boiling point of ammonia) is further cooled? I expected the solution to behave as any other ...
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56 views

Why vapor pressure is unaffected by change in atmospheric pressure [duplicate]

I am a high school student and I am very confused in a topic about "vapor pressure of liquid". Why doesn't a change in atmospheric pressure affect vapor pressure? I think intuitively that ...
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98 views

Calculating molarity of iodine solution after reaction

I made an iodine solution referring to the methodology provided in this link: https://www.thoughtco.com/vitamin-c-determination-by-iodine-titration-606322 $$\ce{KIO3 + 5KI + 3H2SO4->3I2 + 3H2O + ...
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1answer
45 views

Using samples in titrations

I've never done an experiment before. So, the methodology provided in this pdf is quite confusing. Link to the pdf: https://www.canterbury.ac.nz/media/documents/science-outreach/vitaminc_iodine.pdf So,...
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1answer
77 views

What does water saturated oxygen mean? [closed]

What does water saturated oxygen mean in this question: The vapour pressure of water at 80º C is 355 torr. A 100 ml vessel contained water saturated oxygen at 80º C, the total gas pressure being 760 ...
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2answers
82 views

How do you achieve phase separation of a methanol / chloroform solution?

If I'm washing a methanol solution with chloroform, can I just add water in a 1:1 mixture with the methanol and expect it to break? Do I need to do anything else to cause the aqueous phase to separate ...
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1answer
43 views

is boiling point a colligative property? [closed]

I know that elevation in boiling point is a colligative property .But is elevation in boiling point a colligative property ? Boiling point should be a colligative property acc to me bcz it depends ...
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Cleaning solution alternatives for acetate, nitrate, or polyester base motion picture film

I am in search of alternative film cleaning solutions which are safe for the film, me, and the environment. I have used several different professional film cleaning solutions in my many years of ...
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52 views

Finding freezing temperature and osmotic pressure of an ethylene glycol and glycerol solution in water

A water solution is prepared by mixing $\pu{200 g}$ of a ethylene glycol (ethan-1,2-diol; $\ce{C2H6O2}$) solution (20% by weight) with $\pu{500 g}$ of glycerol (propan-1,2,3-triol; $\ce{C3H8O3}$) ...
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1answer
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diprotonated vs monoprotonated inorganic phosphate

We have made confounding observations in the physiology lab working with inorganic phosphate. The cell processes we study rely upon the transport of diprotonated inorganic phosphate. But we get ...
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2answers
226 views

Does Raoult's law hold for immiscible liquids?

I know that Raoult's law holds true only for a non volatile solute in a volatile solvent mixture wherein the vapour pressure of the solution gets lowered due to the addition of solute. Now, first of ...
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1answer
42 views

Density and Viscosity for Solution: 80% Liquid Methane CH4 with Solution of 20% Gas Nitrogen N2 on Surface of Titan (the largest moon of Saturn)?

Problem: Need to estimate the density and dynamic viscosity of such a mixed fluid: 80% Liquid Methane CH4 with solution of 20% Nitrogen Gas N2 with temperature of 94K and pressure of 1,467 hPa (the ...
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3answers
112 views

How are compounds within a complicated mixture detected?

I was reading an article about an independent pharmaceutical watchdog group called Valisure which recently released a report stating that they found Benzene, a toxic substance, in many bottles of ...
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2answers
484 views

Why are entries missing on a solubility data chart for ionic compounds? [closed]

There is a solubility chart in my college chemistry class text for "Solubility of Ionic compounds in water". I have copied and pasted image of chart below. I was surprised to find a dozen ...
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1answer
180 views

Do azeotropic mixtures evaporate proportionally?

Do azeotropes evaporate, without boiling, in proportionate amounts, or does this property describe their behaviour only at boiling point? Concretely, if 91% isopropyl alcohol/water (by volume, i.e. an ...
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57 views

will splitting a solution will keep the concentration values (and moles) the same? [closed]

I have this exercise from my H.W: and I am asked: if we split the solution into 3 different containers equally - how many moles will the solution have in each container? will the Cl- concentration ...
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1answer
53 views

How many boiling points does a mixture of liquids have?

Let's say I have a mixture of two miscible liquids. I want to get the liquids by fractional/pure distillation. My textbook says a mixture boils over a range of temperatures. On the contrary, another ...
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1answer
50 views

Salt solubility and solvent dissociation

A textbook, describing a qualitative test for the $\ce{Al^3+}$ cation in which you use $\ce{NH4Cl}$ and $\ce{NH4OH}$ to precipitate $\ce{Al(OH)3}$, mentioned that the solubility of this precipitate ...
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38 views

What product is created in a zinc - nitrate reaction? [closed]

Question: Place 2 mL of Nitric acid in a test tube and add a small piece of Zinc turning I thought that the overall net ionic equation would be: $$\ce{Zn + 2H+ -> Zn^2+ + H2}$$ Is this correct? ...
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How does the surface to volume ratio of ions and their distribution in solution compare to that of suspended nanoparticles in nanofluids?

I am interested in understanding the heat transfer capabilities of fluids. Nano-fluids are suspensions of nanoparticles (1-100nm sized particles) in a base fluid, often water, oil or glycol. These ...
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1answer
68 views

Hydration vs Dissolution

While revising Thermodynamics and Thermochemistry from revision material published by Arihant publications I encountered the following mentioned statement. During dissolution, the physical state of ...
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44 views

Why in positive deviation from Raoult's Law partial vapour pressure of a liquid component is greater than what is predicted by Raoult's Law?

When my teacher was teaching me positive deviation from Raoult's Law, he told me that in this case $P_{solution}>P_A^°χ_{A} + P_B^°χ_{B}$ He told that here the solute-solvent interactions are ...
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36 views

Osmotic Pressure of Aqueous Solution

The osmotic pressure of an aqueous solution at $25$ Celsius is $92.0$ $kPa$. Calculate the boiling point of the solution. (Assume that the density of the solution is $1.0$ $g/mL$, ignore the mass of ...
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Why does the non-volatile solute go into the liquid part of the the solution when a solution containing non-volative solute is freezed?

My teacher gave the following diagram in the class notes. He said that when a solution containing a non-volative solute (for e.g. a solution of $\ce{NaCl}$ in water) is freezed, then there will be ...
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1answer
211 views

What is the derivation for the expression of depression in freezing point?

In my textbook, it is written that the expression for depression in freezing point is $$ΔT_{f}=K_{f}\cdot m$$ where $ΔT_{f}$ is the freezing point depression (defined as positive value), $K_{f}$ is a ...
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1answer
211 views

Why lowering of vapour pressure is not a colligative property?

In my textbook, it is written that lowering of vapour pressure is not a colligative property but relative lowering of vapour pressure is a colligative property. But why is that? There is literally no ...
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1answer
112 views

Why is change in volume of the solution zero in case of an ideal solution?

In my textbook it is written that $ΔV_{mix} = 0$ for ideal solutions i.e. $V_{solution} = V_{A} + V_{B}$. But why is this true? There is literally no explanation in my textbook as to why this is true. ...
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1answer
29 views

Where does the residue accumulate in the boiling point composition curve?

My teacher was teaching me the boiling point composition curve for fractional distillation and in the class notes he gave the following diagram (I have given below). It says that the residue starts ...
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144 views

Will potassium permanganate react with ferric chloride?

I came across a question : Which of the following compound does not decolourise an acidified solution of $\ce{KMnO4}$? Answer was: After doing a bit of research I found that $\ce{KMnO4}$ oxidises $\...
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140 views

A solution is cloudy at lower concentration and becomes clear at higher concentration. Why?

This might be just an "everyday life science" question. I am a university professor but not in Chemistry so please educate me. Today I was adding some floor cleaner formula to water as ...
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1answer
126 views

Can we compare the vapour pressure of solutions whose concentrations and temperature is known?

If we have some solutions, in which we know the temperature and concentration of the solute particles, can we compare their vapour pressures? Original question: Which solution has the highest vapour ...
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2answers
264 views

Azeotropic mixtures and Raoult's Law

So I find this everywhere: "Mixtures showing large deviations from Rault's law form azetropic mixtures at specific compositions" My questions are: (a)Why is it so?Why deviation from Raoult's ...
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1answer
53 views

Does the composition of a solution keep changing when being boiled? [closed]

The mole fractions of the components of vapours aren't the same as those of the liquid-liquid solution (unless the solution is azeotropic), this implies a change in the composition of the liquid ...
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56 views

Henry's Law and "Gases in Vapour Phase"

I found the following definition of Henry's Law in my textbook: "The partial pressure of the gas in vapour phase is proportional to the mole fraction of the gas in the solution." My ...
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1answer
375 views

To calculate total vapour pressure of a solution

Question: 1 mole each of A and B were mixed to obtain an ideal solution of which one mole went to the vapour phase at equilibrium. If $P°_\mathrm{A} = \pu{100 torr}$ and $P°_\mathrm{B} = \pu{900 torr}$...

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