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Questions tagged [aqueous-solution]

For questions relating to compounds dissolved in water and resulting reactions.

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2answers
310 views

Dangers of expired bleach?

I have some unopened Clorox bleach bought over a year ago (at $8.25~\%\ \ce{NaOCl}$) and read on Wikipedia that bleach naturally decomposes according to $$\ce{3 NaOCl (aq) -> NaClO3 (aq) + 2 NaCl(...
2
votes
1answer
276 views

Why is the hydrolysis of the conjugate base of a weak acid neglected in buffer solutions?

Consider a solution which contains a weak acid and the salt of its conjugate base with a strong base. e.g. $$\ce{CH3COOH + H2O <=>[$K_\rm{a}$] CH3COO- + H3O+}\tag1$$ $$\ce{CH3COO- + H2O <=&...
1
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1answer
102 views

Grams of bicarbonate vs realeased CO2?

So, it's been a good two years since I've done chemistry and I have my first university lab in a few days and I'm sort of freaking out because I can't even remember how to do stoichiometry properly. ...
3
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0answers
601 views

Non existence of B3+ in solution [closed]

I read that B3+ ions do not exist in aqueous solution, because hydration energy cannot compensate for the sum of first three ionisation energies. This leads me to the following questions: If boron (...
4
votes
1answer
203 views

How would an increase in the concentration of a sucrose solution affect the rate of its acidic hydrolysis?

Regarding the acidic hydrolysis of sucrose $$\ce{\underset{sucrose}{C12H22O11} + H2O + \underset{catalyst}{H+} -> \underset{glucose}{C6H12O6} + \underset{fructose}{C6H12O6} + H+},$$ I think ...
2
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1answer
702 views

Why are different colors, according to sugar concentration observed in Benedict's test?

Colors range from green yellow orange to red. How does the sugar concentration and Cu2O concentration cause this? I know Cu2O is red. Why is there a green or yellow color instead of just red or some ...
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1answer
267 views

Disproportionation Reaction [closed]

This is the problem I am trying to balance for redox: $$\ce{HXeO4 -> XeO6^{4-} + Xe + O2}$$ It is supposed to be in a basic solution. However, my answer does not contain $\ce{OH-}$ on either side:...
2
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1answer
59 views

Do chemical garden coral formations leach toxins?

Short version, I want to make a coral garden with sodium silicate and salts, and I would like to put that in my fish tank, but I'm concerned about the fish getting poisoned. https://en.wikipedia.org/...
2
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0answers
2k views

Best way to dissolve/emulsify beeswax and carnauba wax in water-based solution

What I can use to dissolve beeswax and carnauba wax and keep it in an aqueous solution? I do not want to use ethanol or acetone as they are too harsh. I am adding about $\pu{5\%}$ wax to a $\pu{16oz}$...
-1
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1answer
858 views

Why does copper sulfate disassociate into Cu+2 and SO4-2 when dissolved in water?

I'm trying to understand why exactly copper sulfate disassociates into $\ce{Cu^{2+}}$ and $\ce{SO4^{2-}}$ ions? How is it calculated? I'm trying to find information but it seems as if it is treated as ...
2
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2answers
2k views

Why doesn't a buffer solution change ph(Appreciably?)

Consider a buffer solution containing weak acid $\ce{CH3COOH}$ and its salt $\ce{CH3COONa}$: \begin{align} \ce{CH3COOH &<=> CH3COO- + H+} \tag{1}\\ \ce{CH3COONa &-> CH3COO- + Na+} \...
1
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1answer
380 views

Crystallization in a solution of 2 or more solutes

This is a very basic question I found myself wondering. For simplicity's sake, we'll say it is a super saturated aqueous solution of an equivalent measure of sugar and salt. As the solution cools and ...
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0answers
85 views

How to mix copper powder, Polyvinyl alcohol and deionised water into a paste

I'm trying get a paste of the materials mentioned above.I am trying to maximize the amount of copper, so far I have tried 30% cu and 35% by volume pva and copper, as well as 25% cu,50% pva and 25% ...
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0answers
144 views

when preparing a supersaturated solution, does the crystalization occur immediately?

I have gotten slightly confused on how the crystallization process exactly occurs when preparing a supersaturated solution. Say we prepare a supersaturated solution by the usual process, first ...
3
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2answers
42 views

Why wouldn't you consider the [H+] produce from the weaker acid in a mixture of two acid?

Calculate the pH of a solution that contains $\pu{2.0 M}$ $\ce{HF}$ and $\pu{2.0 M}$ $\ce{C6H5OH}$. Also calculate the concentration of $\ce{C6H5O-}$ in this solution at equilibrium. In these ...
2
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0answers
56 views

How fast does atmospheric carbon dioxide dissolve into strongly basic solution?

I'm conducting some pH measurements with solutions containing NaOH and I'm a bit concerned that carbon dioxide will dissolve and affect my measurements by lowering the pH according to the reaction: $$\...
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1answer
43 views

Peroxide without hydrogen [closed]

How come we always see hydrogen peroxide and never peroxide by itself. Is there such a thing as peroxide ? Does this exist in nature? Why is hydrogen always associated with it? Please note: First ...
-1
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2answers
1k views

Is it necessary to write state symbols in ionic equations and if so, why?

I understand that it is necessary to use state symbols in an equation with compounds shown, such as: $$\ce{NaCl(aq) +AgNO3 (aq) -> NaNO3 (aq) +AgCl(s)}$$ But is it necessary to use state symbols ...
8
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2answers
640 views

How can we tell the particle size of solutes in solutions?

This is a general question in regard to solutes dissolving into solvents. I am interested in the reality of the particle size of the solute during dissolution. For example, take $\ce{NaCl}$ and ...
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0answers
33 views

Charge Balance and power law?

I've come across a statement in a paper* that's poorly explained, and I can't work out the reasoning behind it. I suspect this is embarrassingly basic, but could anyone please explain the theory ...
0
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1answer
708 views

In a reaction between Calcium Ammonium Nitrate or Urea with water, does Nitrogen Content and Purity affect how cold the solution gets?

Recently, I bought an ice pack that contained Calcium Ammonium Nitrate, and realized that it really didn't get cold. I came to the conclusion that perhaps Urea is more effective, yet it is still ...
3
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0answers
85 views

Chemistry Behind TMOS Aerogel

I have found out how to make silica aerogel. Currently, the solution that I need to create to make the gel requires tetramethyl orthosilicate or TMOS. Furthermore, the procedure requires me to make ...
0
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1answer
6k views

Solubility of Aluminium Hydroxide in Sodium Hydroxide Solution

Aluminium hydroxide is not soluble in water at all, however I was doing some reading and read that it does in fact dissolve in a solution of sodium hydroxide. This just seemed a bit strange to me, so ...
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0answers
48 views

Selective Salt Extraction

I have a mixture of compounds that have a very large amount of NaCl dissolved after pH neutralization. The reaction I'm attempting is to conjugate a quinolone variant to a macrocylic via the formation ...
2
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2answers
134 views

Partial reactions in redox formation of rust

In the iron oxidation that results in rust, the first step is to steal 2 electrons from $\ce{Fe}$. The main thief is said to be the oxygen dissolved in water, witch uses the stolen electrons to form $\...
2
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0answers
119 views

Narrow range of pH for the formation of polyoxometalate clusters

The molybdate ion in aqueous solutions, speciates as clusters known as polyoxometalates (POMs) when it is acidified, but these clusters only aggregate in a very narrow pH range "polymeric range" in ...
4
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1answer
309 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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2answers
2k views

Will an aqueous sodium hydroxide solution degrade over time?

I have a chiller bath, which is attached to a 150 ton cooling unit through 4" PVC pipe. The bath itself holds around 5000 gallons of water, and is made of 304 stainless steel. It constantly circulates ...
4
votes
1answer
154 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 ...
4
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0answers
113 views

Why does viscosity decrease when divalent cations are dissolved into aqueous solutions of sodium carboxymethylcellulose?

Sodium Carboxymethylcellulose (CMC/NaCMC/Aqualon) is a common product used in many instances for its unique properties, especially its ability to make solutions viscous. It is well known that the ...
1
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1answer
1k views

Dissolution of Pentahydrate of Copper Sulfate

I'm having some difficulty understanding how the pentahydrate of copper sulfate dissolves in water. I understand how polar molecules work, and how things dissolve in water, but I can't get my head ...
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0answers
50 views

Alternatives to carbonates?

This isn't strictly 'pure' chemistry but the knowledge to answer it is probably much closer to chemistry than any other subject. The question is a simple one - are there any other non-toxic aqueous ...
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0answers
358 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 ...
4
votes
1answer
184 views

Could we reach a pH of 4.9 by blowing through straws?

According to Wikipedia's article on Breathing: The permanent gases in gas we exhale are 4% to 5% by volume more carbon dioxide and 4% to 5% by volume less oxygen than was inhaled. If I started ...
0
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1answer
222 views

Why does the iron rust with less salt

For my school project I was going to measure the rate that salt has on the rusting of iron. To do this I set up an experiment where I had 15 beakers containing 200 milliliters of distilled water. I ...
2
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0answers
70 views

Vacuum filtration: will Polymer elements interfere with the vacuum?

I am doing an experiment with vacuum filtration, where a Nylon filter is used to create a membrane (marked in pink in the picture attached). When I use the membrane, it frequently breaks in the ...
2
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0answers
32 views

Extimating the repartition of water between hygroscopic compounds

Sulfuric acid is sometimes used as a drying agent. According to literature, one possible application is, for instance, in the drying of bromine. Some questions came to my mind: which concentration ...
0
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1answer
2k views

Solubility of potassium nitrate and potassium chloride

Why more water is needed to dissolve potassium chloride than potassium nitrate of equal amount? Is it to do with the reaction that occurs when the compounds dissolve or the properties of the compounds?...
1
vote
1answer
1k views

Van't Hoff factor for citric and phosphoric acids

I am trying to determine the van't Hoff Factor for citric and phosphoric acids. When phosphoric acid is in aqueous solution, it dissociates as follows: $$\ce{H3PO4 ->H2PO4- + H3O+}$$ Does this ...
4
votes
1answer
463 views

Temperature change and gas evolution for vinegar and baking soda experiment

This is sort of 2 questions in 1, but I think they are related. Could someone please explain why this endothermic reaction doesn't further decrease the temperature when the amount of baking soda is ...
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2answers
3k views

Why would a solution of FeCl2 appear brown/yellow sort of like FeCl3?

If we prepare a solution of $\ce{FeCl2}$ by dissolving solid $\ce{FeCl2}$ powder in water, supposing the bottle of $\ce{FeCl2}$ was left open for sufficient time, is it possible for $\ce{FeCl2}$ to ...
1
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1answer
517 views

Will water allow salts to be dissolved in methanol (that are otherwise poorly soluble)?

If we make a mixture of water, methanol and a salt like $\ce{FeCl2}$, $\ce{NaCl}$ etc, will the ability of water and methanol to mix allow $\ce{FeCl2}$ and $\ce{NaCl}$ to be a part of this mixture and ...
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3answers
76 views

Finding ions in water samples

So for a school chemistry assignment I was given 5 water samples and a bunch of different reagents to help me find out what was in the solutions. I'm stuck on two. The first one had a pH of 7 and ...
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1answer
515 views

If Ag2SO4 dissociates into 2Ag+ and SO4^2-, Why doesn't SO4^2- dissociate into oxygen and sulphur? [duplicate]

When $\ce{Ag2SO4}$ dissociates it becomes $\ce{2Ag^+}$ and $\ce{SO4^2-}$ Why doesn't the $\ce{SO4^2-}$ dissociate further into oxygen and sulfur?
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0answers
387 views

Does lithium carbonate react with water once dissolved in it?

Lithium carbonate has limited water solubility, but it is still soluble. My question is whether or not lithium carbonate reacts with the water once it is in aqueous solution. Any insight would be ...
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1answer
839 views

Calculating pH of solution of phosphoric acid and ammonia

What is the $\ce{pH}$ of the solution created when $\ce{50ml}$ of $\ce{0.2M}$ $\ce{H3PO4}$ is mixed with $\ce{50ml}$ of $\ce{0.4M}$ $\ce{NH3}$? This problem can be approached rigorously. That's what ...
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0answers
38 views

Volume change of solute addition to solvent

When making and manipulating high concentration stock solutions of sugar excipients, is there a way to predict the corresponding volume effect that occurs? I am asking in order to be able to create ...
3
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4answers
4k views

Long-term storage of Ascorbic Acid mixed with Sodium Bicarbonate

Every day I mix two parts of ascorbic acid powder with 1 part of sodium bicarbonate powder and place the resulting powder into an airtight container. I have noticed that if the resulting powder is ...
0
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1answer
50 views

Does the addition of acid change alkalinity? [closed]

I'm attempting to speed up the dissolution of calcium carbonate by the addition of hydrochloric acid. However, I'm using the calcium carbonate as a source of carbonate for a water sample. But would ...
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0answers
46 views

pH change with pressure in a bicarbonate buffer system

Looking at small scale bioreactors with no added pressure (1atm) compared to a commercial bioreactor which is pressured to 5 psi, where both have the same concentration of sodium bicarbonate, if both ...