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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-1 votes
2 answers
36 views

Electrolysis of Solutions

So far I've only encountered formulas to solve for solutions of single molecules while learning about electrolysis, i.e. H2O or FeCl3. This generally has involved determining the resultants, ...
0 votes
0 answers
87 views

Colligative properties and binary phase diagrams

I'm having troubles with colligative properties and how to relate them to binary liquid-vapour and solid-liquid phase diagrams. First of all, in my book it is indicated that colligative properties are ...
0 votes
1 answer
27 views

Is the process of volume decrease in NaOH solutions reversible during evaporation of water from the solution? [closed]

While preparing w/w 50% NaOH solution I noticed a decrease in solution volume (5-10mL) in a 2L volumetric flask, so I am wondering if there is an increase in water volume during the water evaporation ...
-1 votes
0 answers
24 views

Estimation of hydration energy

https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Book%3A_Introduction_to_Inorganic_Chemistry_(Wikibook)/09%3A_Ionic_and_Covalent_Solids_-_Energetics/9.12%3A_Lattice_Energies_and_Solubility ...
2 votes
0 answers
69 views

Buffer solution of NaH2PO4 and Na2HPO4

We have this exercise without solutions From a 0.2 M $\ce{NaH2PO4}$ solution and a 0.2 M $\ce{Na2HPO4}$ solution, a buffer solution with pH = 6.8 is to be prepared. The total concentration of $\ce{...
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3 votes
2 answers
163 views

Calculate the titer of a solution

I hope this is the right place to ask. We have this exercise without solution One litre of diluted sodium hydroxide solution (c = 0.15mol/litre) is to be prepared in the laboratory. The titer from ...
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5 votes
1 answer
452 views

Why is water present in "pure" nitric acid and RFNA and WFNA?

Various types of nitric acid have been used in rocket fuels as oxidisers (RFNA is red fuming nitric acid, WFNA is white fuming nitric acid) as they are often hypergolic with a wide variety of fuels. ...
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1 vote
3 answers
80 views

Silver recovery from sodium hydroxide solution

I have washed graphic film with sodium hydroxide solution removing the silver emulsion. Is there any way to now recover the silver from solution?
-2 votes
2 answers
72 views

Are mixtures of finely ground solid fertilizer compounds stable? [closed]

If I had a combination of the following as finely ground powders, would it be relatively stable, or would they react to form other compounds? Sodium Nitrate Ammonium Nitrate Calcium Nitrate Potassium ...
1 vote
0 answers
29 views

Making a reagent preparation simpler that requires pH adjustment

I have a basic question on a reagent (solution) preparation. Here are the steps that I take to prepare the reagent: Weigh the chemical (solid form, ammonium bicarbonate) and dissolve with DW to make ...
-1 votes
1 answer
46 views

Does addition of solute affect the rate of condensation?

I know that addition of a non-volatile solute in a pure solvent effects the rate of evaporation as the number of molecules leaving the liquid bulk per unit time decreases. However when the rate of ...
2 votes
3 answers
274 views

Why are the vapor pressure of toluene and benzene different?

We learnt to apply Raoult's law for the ideal solutions. When the questions are asked, they tell that the intermolecular forces of toluene and benzene are equal. But in the same question, they provide ...
3 votes
1 answer
52 views

is it possible to make crystals of multiple organic compounds that form a homogenous mass under normal conditions

I was thinking about crystals of organic compounds recently after I had to clean beeswax off a pot. it's an extremely tedious process to remove. you have to boil water in the pot and then continually ...
0 votes
0 answers
25 views

Why do we cool the solution after melting it?

We conducted an experiment to analyze the molar mass of a solid by observing the freezing point depression it brought to cyclohexane. In short, the experiment procedure is as follows the freezing ...
1 vote
0 answers
42 views

Would a container made of sugar eventually dissolve if filled with a sugar-saturated solution of water?

Suppose you had a bottle made of sugar glass, and filled it with water that was already saturated with sugar. I know that with a fully saturated solution of sugar in water, no additional sugar can ...
-3 votes
1 answer
51 views

Does concentrated HNO3 oxidize aluminium to form a protective oxide layer, or is the oxide layer already present so HNO3 is unable to react? [duplicate]

Sources on the internet like this one only say that aluminium does not react with concentrated or dilute $\ce{HNO3}$. I have seen other related questions on this site but none answers my question ...
-5 votes
1 answer
34 views

Why is 10 times phosphate-buffered saline more acidic (~6.9) than 1 time phosphate-buffered saline (~7.4)? [closed]

Recently, I've been told that similar pH shift (of about 0.5 units) was observed with 20 times NPS solution as well. In case of NPS the authors provide the following recipe for the 20 times solution: ...
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4 votes
4 answers
106 views

Determining the concentration of a very small sample of sulfuric acid

How can we determine the concentration of sulfuric acid in a very small sample? We are working on a “mechanical” process that transports a very small amount of sulfuric acid to an instrument and we ...
3 votes
0 answers
31 views

How to calculate composition of alcohol/water mixture to achieve given concentration of alcohol vapors in air for calibrating a DIY breathalyzer?

I made a breathalyzer using a MiCS-5524 gas sensor. I would like to calibrate it so it can be close to accurate. e2v technologies — MiCS Application Note 4, Using MiCS Sensors for Alcohol Detection (...
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1 vote
0 answers
58 views

Is mass of solute included in calculation of enthalpy of solution? [duplicate]

$$ \begin{array}{lrrrr} \hline & \ce{MgSO4} & \ce{K2SO4} & \ce{KNO3} & \ce{NH4NO3} \\ \hline m/\pu{g} & 15 & 15 & 15 & 15 \\ M/\pu{g mol^-1} & 120.37 & 174.26 ...
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1 vote
1 answer
72 views

Why did The Action Lab say that solutes that don't dissolve as well in hot water are exothermic?

Somewhat recently, The Action Lab made a video called "Why does this powder only dissolve in cold water?" , saying the powder which was calcium acetate dissolves in cold water better than in ...
5 votes
1 answer
211 views

Why aluminum does not form ammonia complex ion?

I learned in my textbook that zinc forms more stable complex ion with NH3 than OH- because NH3 has only one lone pair and that makes repulsion between d orbital electron in zinc and lone pair electron ...
0 votes
0 answers
24 views

When is a solution supersaturated? [duplicate]

When does a solution become supersaturated? From a little search on Google I found that, increasing the temperature of a saturated solution and adding some more solute until it starts to precipitate ...
-1 votes
1 answer
60 views

How do I interpret the dissolution rate unit? [closed]

I have found a paper (link) that is interesting for my research project. The dissolution rate unit in this paper is described as $\pu{mol/cm^2/s}$. For my project I would need the dissolution speed ...
1 vote
0 answers
25 views

Can micelles form in a polar-vacuum interface?

As the formation of micelles depends on, among many factors, the difference of polarity/relative permittivity of the solvents involved with the surfactant, I'm wondering if a polar-vacuum system is ...
0 votes
0 answers
84 views

Disposal of Metal Ion Solutions After Flame Test

I just bought a flame-test spectroscopy kit to use with our small homeschool group. It includes calcium chloride, potassium chloride, strontium chloride, and lithium chloride. I also bought a bottle ...
10 votes
3 answers
2k views

Why is there a decrease in the total volume when NaOH dissolves in water?

When a solute is added to a solvent, the volume of the solution should be equal to the sum of the individual volume of the solute and solvent (i.e total volume), right? But why is there a decrease in ...
-1 votes
1 answer
25 views

Will the solid formed after dehydration of a disodium hydrogen phosphate + sodium hydroxide solution be hygroscopic at STP?

Given a solution consisting of disodium hydrogen phosphate + sodium hydroxide (approaching a pH of 12), will the solid formed after dehydration of the solution be hygroscopic at STP? Which salts are ...
-2 votes
2 answers
85 views

Can ions be acids or bases?

Consider a sulfate ion, its considered a weak base. Yet I thought bases and acids were compounds meaning they were always electrically neutral? Why is a sulfate ion then considered a base? And how ...
-1 votes
1 answer
98 views

Safely removing sodium hypochlorite crystals from hard-to-reach surfaces

I have a small bathing whirlpool which wasn’t used for over ten years. It is built into the ground and I cannot reach the disinfectant container to replace it with a new one. I can access the fill-...
2 votes
2 answers
49 views

How to remember what measure of concentration to use for colligative properties

Like the title says, how do I remember what measure of concentration(molality, molarity, mole fraction) to use for various colligative properties such as increase in boiling point when a non-volatile ...
-2 votes
1 answer
102 views

How does adding oxalic acid to water change the volume of the solution?

Does $\pu{87.4 mL}$ of $\ce{H2O}$ and $\pu{12.6 g}$ of $\ce{HOOC-COOH.2H2O}$ create $\pu{100 mL}$ of a solution? So in our practical class our teacher wanted to make $\pu{100 mL}$ $\pu{1 M}$ aqueous ...
1 vote
1 answer
77 views

Finding the density

35.6g of NaOH is dissolved in 150g of 20% NaOH solution. What is the density od the solution? I have tried solving this problem, but I 've come across a few obstacles. Firstly, I found the mass of ...
5 votes
1 answer
189 views

Why does the 1H NMR spectrum of methacryloyl chloride show two singlets instead of two doublets for vinyl protons?

Based on what I have understood, for methacryloyl chloride there is a geminal coupling of the vinyl protons since they are not chemically equivalent. Why are two singlets observed for vinyl protons ...
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1 vote
1 answer
62 views

Is vapour pressure truly a colligative property?

Colligative properties are generally defined as A colligative property depends only on the ratio of the number of particles of solute and solvent in the solution, not the identity of the solute. ...
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0 votes
0 answers
32 views

How to measure pottery glaze leaching?

I am looking for a way to know if glazes from pottery leach chemical compound in water. Those are usually metal ions: cobalt, manganese, chrome, etc. The procedure would be to place hot water in the ...
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-1 votes
3 answers
396 views

Why does equilibrium of ice and water only exist at 273K at normal pressure?

I am a high school student and I am a little confused in the concept of spontaneity of a reaction and how equilibrium works for a reaction, I got some confusions: Let's take example of freezing of ...
1 vote
0 answers
49 views

What is the necessary and sufficient condition for a mixture to be ideal?

I am trying to understand some concepts from solution thermodynamics related to ideal mixtures and fugacity. My main question is what is the necessary and sufficient condition for a mixture to be an ...
-3 votes
1 answer
51 views

pH calculation of a mixure containing 2 strong acids and a buffer mixture

Calculate the pH of a mixtureof 10 mL 0,1 M HCl ; 5 mL 0,1 M HNO3 ; 10 mL 0,2 M HAc ; 15 mL 0,4 M NaAc. My understanding was that I have to find the [H+] by: finding the concentration of the products ...
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4 votes
1 answer
102 views

Variation of conductance of saturated aqueous solution with temperature

The following question was asked in JEE Mains 2020: Let $C_{\ce{NaCl}}$ and $C_{\ce{BaSO4}}$ be the conductances (in S) measured for saturated aqueous solutions of $\ce{NaCl}$ and $\ce{BaSO4}$, ...
0 votes
0 answers
37 views

How do I determine if a nucleophile attacks the electrophilic atom directly or indirectly?

How do I determine if a nucleophile attacks the electrophilic atom directly or indirectly? For instance a nucleophile could attack the carbon in a molecule with a carbonyl directly, but in another ...
2 votes
0 answers
53 views

Gouy-Chapman model

Recently I have been investigating the problem of a neutral solutions (with equal number of anions and cations) interacting with an infinite surface $z=0$ with electrostatic potential $\phi(z=0)=\...
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-3 votes
2 answers
193 views

why is humid air an example of liquid gas solution instead of gas gas solution? [closed]

In my textbook, humid air is given as an example to liquid in gas solution. But isn't humidity the amount of water vapour (gas) and therefore should be gas in gas solution?
-2 votes
1 answer
55 views

Can Bromophenol Blue Sodium Salt, and Pentane be safely mixed/in contact with each other?

I'm trying to determine if powdered Bromophenol blue is safe to mix with Pentane. I would only need a tiny amount of dye, just enough to tint the pentane. I need to use pentane for it's specific ...
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0 votes
0 answers
34 views

Liquid water barrier and water vapor permeable membrane sheets

I am running an experiment where I am trying to maintain the relative humidity of a thermally insulated chamber. I am successfully able to hold the humidity using different salt solutions (NACL-75% RH,...
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-2 votes
1 answer
60 views

Why doesn’t ferrous sulfate appear orange in vinegar?

When I mix ferrous sulfate crystals with water, the solution almost immediately turns orange. However, when I mix ferrous sulfate with vinegar, it doesn’t change colors. Why is this?
-4 votes
1 answer
35 views

Separation methods [closed]

I put some iron nails in water, and obviously, those started oxidizing, making those hydrogen bubbles. Some days after, the water was orange, indicated that the FeO has just dissolved in it. I found ...
3 votes
1 answer
29 views

Clean a filler machine used to dispense epoxy resin

I am dispensing epoxy resin and at times epoxy hardener through a filler machine. It needs to be cleaned after each run, but rather than do a complete tear down, I'd rather be able to complete a &...
1 vote
1 answer
69 views

What factors influence the upper size limit of micelle's?

Is there an inherent size at which micelle's cannot grow larger in volume? I have been trying to find a quantifiable method of measuring a size limit with all the variables that affect micelle ...
9 votes
1 answer
641 views

What is the maximum osmotic pressure that can be exerted with water as the solvent at room temperature?

Lets say we have a membrane which separates a tank of pure water from a tank of water saturated with a solute(there are also undissolved chunks of solute which can immediately dissolve if water is ...
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