Questions tagged [aqueous-solution]

For questions relating to compounds dissolved in water and resulting reactions and acid-base equilibria.

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6
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2answers
11k views

Azeotropes and separation by distillation?

I have just recently learnt the theory of fractional and normal distillations and the basics of maximum and minimum boiling azeotropes. Most books say that the components of the mixture forming an ...
6
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1answer
17k views

Is there a way to calculate how fast water will cool?

Is there a way to calculate how fast water will cool if you know the water's starting temperature and temperature of the environment that you put it in, such as a freezer?
5
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2answers
35k views

Does dissolving salt in water change the pH?

I am particularly interested in the effect or lack of effect of dissolved NaCl in regards to pH in water. It would be interesting also if anyone has any insight for other salts and their effects. ...
3
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1answer
5k views

Hypochlorous acid mechanism

When hypochlorous acid is dissolved in water, is it the chlorine atom or the oxygen that serves as the anti microbial agent?
2
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1answer
2k views

Is there a database which give reaction constant?

For instance, I have a chemical reaction like : $$\ce{Fe^{2+} + $0.5$O2 + H^{+} ->Fe^{3+} + $0.5$ H2O}$$ And I would like to use Action-Mass law, but I need to have equilibrium constant for this ...
2
votes
1answer
7k views

Reaction of sulfate ion in copper sulfate electrolysis

I am planning to try copper plating a piece of metal by performing electrolysis on an aqueous solution of copper sulfate. I plan run an electrical current with the metal I want to plate as the cathode ...
1
vote
3answers
53k views

How to convert from w/w% to molarity?

After reading a number of explanations about it after googling, I'm a bit confused on this. Some explanations are doing it using a solution density, others aren't, though most are. On one site it's ...
0
votes
1answer
6k views

Is there a difference between ‘ammonium hydroxide’ and ‘aqueous ammonia’?

Water ($\ce{H2O}$) can be added to ammonia ($\ce{NH3}$) in order to form ammonium hydroxide ($\ce{NH4OH}$): $$\ce{NH3 + H2O -> NH4OH}$$ But we know that ammonia is gaseous at STP so writing $\ce{...
-7
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1answer
1k views

Is Phosphate (PO4 3-) solube in water? [closed]

Josh~ Superphosphate is used instead of just phosphate because superphosphate is a compound whereas phosphate is an ion. This means that phosphate must attach itself with a cation in order to give a ...
12
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2answers
366 views

Water exchange at Al (III)

Why is the rate of water exchange at Al(III) centres so slow ? According to this medical book (p.5) it is $10^{5}$ times faster at Mg(II).
10
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1answer
5k views

Why aren't the copper(II) ions in CuSO4 precipitated by hydroxide ions from water?

From my own experience and literature, I know that $\ce{CuSO4}$ is well soluble in water and dissociates into $\ce{Cu^2+}$ and $\ce{SO4^2-}$. $\ce{Cu(OH)2}$, however, is not: $K_\mathrm{sp} = 2 \cdot ...
9
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2answers
301 views

Vapor Pressure Paradox

This is quite an interesting situation I had thought of. Consider two beakers, each containing $\pu{180 g}$ of water. Also, suppose one of the two has $\pu{1.8 g}$ of glucose dissolved in it. Let's ...
8
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2answers
10k views

Can sodium bicarbonate be considered an acid?

I was reading about acids and bases today and finally decided to question the statement that "baking soda is a base." Let's start with the dissolving of baking soda, $\ce{NaHCO3}$. The equation to ...
6
votes
5answers
19k views

How to dissolve steel without affecting aluminium alloy

Disclaimer: I have very limited knowledge of chemistry My problem is the following: I have motorcycle part made from some sort of Aluminium alloy - most probably 6005, 6061-T6 or 7005. And inside of ...
6
votes
3answers
2k views

Will this reaction form magnesium carbonate?

I have magnesium oxide pills I take. I know if I dissolve them they'll form magnesium hydroxide, and I'm trying to make pure magnesium from my pills. I've come up with a double replacement reaction, ...
6
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0answers
3k views

Is iron(III) carbonate stable in water?

I searched for this onsite already, and also found the following answer on Quora: In aqueous environment, iron(III) is bound by water molecules and exists as $\ce{[Fe(H2O)6]^3+}$. Due to strong ...
5
votes
1answer
467 views

Trichloride ion (c.f. triiodide ion)

While triiodide ion is commonly known, why is that trichloride ion (and its salts) almost unheard of? While it does exist according to literature, why is the stability of trichloride ion in aqueous ...
5
votes
1answer
1k views

How is NaOH able to clear a solution of Paraformaldehyde?

While making a solution of $4~\%$ para-formaldehyde for immunohistochemistry (to fix the tissue), we add para-formaldehyde into water and stir. It looks like a chalky supersaturated solution even ...
5
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2answers
458 views

Decrease in temperature of an aqueous salt solution decreases conductivity

Why does the conductivity of a water solution drop as the temperature decreases? How are these two related?
4
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1answer
518 views

Why do aqueous solutions always have to be electrically neutral?

I was reviewing some analytical chemistry and stumbled upon a section that explained the imperfection of using a salt bridge. It said that the using dissimilar ions is a problem because in, for ...
4
votes
1answer
1k views

Why does pouring soda slowly and smoothly seem to keep more of the carbonation?

So, I caught myself gently pouring a can of soda into a cup of ice (making sure that there was room for air to move through so the stream of soda from the can to the cup was consistent and even) ...
4
votes
1answer
416 views

How many protons does phenolphthalein lose in basic solutions?

So, I've looked it up and Wikipedia claims that two protons are released by Phenolphthalein when pH is over 8.2, but I've seen other sources that claim only one proton is lost. So, is it really just ...
4
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2answers
2k views

Does H2CO3 exist in solution?

When $\ce{CO2}$ reacts with water, it supposedly forms $\ce{H2CO3}$, which is the aqueous form of $\ce{CO2}$. But it is hard to isolate, but its $K_\mathrm{a}$ value is pretty low (on the order of $10^...
4
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1answer
2k views

What are the active ingredients of shampoo, and how do they work?

After seeing one too many TV commercial about the fantastical properties of different high-profile shampoo products all "with documented effect" it suddenly struck me that I never actually researched ...
4
votes
2answers
3k views

Why is water ignored in the ionic equilibrium of HF?

While trying to understand the solution of a problem given in my textbook, I realized I'm having some difficulty with the solution. The problem is as follows: The ionization constant of $\ce{HF}$ ...
3
votes
1answer
2k views

Decomposition of iron(III) acetate?

I recently asked about the synthesis of iron (III) acetate. I want a rather concentrated solution to use as a calligraphy ink (which will be dissolved in alcohol/water). Will it be okay to heat the ...
3
votes
1answer
293 views

How can I measure the amount of quinine in a home-made tonic water?

I'm into mixology, and lately I've been looking into experimenting with home-made tonic water, by extracting quinine (quinine salts) from cinchona barks in an acidic aqueous solution. I've read a bit ...
3
votes
2answers
24k views

What are the effects of adding water to a system at equilibrium?

Given the reaction $\ce{NaCl~(s) <=> Na+~(aq) + Cl^{-}~(aq)}$. $\ce{NaCl}$ is added to water and equilibrium is reached. Does the reaction shift to the left/right/not shift at all if more ...
2
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2answers
7k views

Why is sodium sulfate a neutral salt [duplicate]

When I have a solution of $\ce{Na2SO4}$, the sodium sulfate should ionize: $$\ce{Na2SO4(aq) -> 2Na+(aq) + SO4^{2-}(aq)}$$ In my mind, the sodium ions should just float around, but because $\ce{...
2
votes
0answers
638 views

Precipitation of citric acid by CaCl2 and Ca(OH)2? [closed]

I need to precipitate citric acid from an aqueous solution in the form of calcium citrate. There are, to my knowledge, two different methods of doing this: using $\ce{CaCl2}$ and which will react ...
2
votes
1answer
837 views

Light scattering in sulfur colloids

Recently I did a reaction in the lab (the reaction itself is not important) whose product was colloidal sulfur. As I watched the sulfur particles form I noticed something strange: At first the sulfur ...
2
votes
1answer
1k views

Calculating approximate pH of polyprotic acids

When I took up ionic equilibria and titrations after a long break, I found it hard to solve the questions regarding pH calculations of polyprotic acds. Consider these two questions as examples:- ...
2
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1answer
1k views

Why is lithium bromide used in absorption refrigerators?

Lithium bromide refrigerator Why is lithium bromide used in absorption refrigerators? It is more expensive than sodium chloride. The wikipedia article on lithium bromide says it is extremely ...
2
votes
1answer
102 views

Diffusion of CO2 and O2 in Water/Atmosphere System

Consider the following experiment: One reservoir of pure water is interfacing the atmosphere at standard condition. Both are at rest and at the same temperature. Both have no internal gradients (ie:...
2
votes
0answers
269 views

Why do some insoluble salts undergo slow chemical reaction instead of dissociation in water?

$$\ce{PbCl2 + H2O ->[\Delta] Pb(OH)Cl + HCl}\tag{1}$$ $$\ce{2ZnCO3 + H2O ->[\Delta] Zn2(OH)2CO3 + CO2}\tag{2}$$ $$\ce{2NiS + 2H2O → Ni2(OH)2S + H2S}\tag{3}$$ $$\ce{Hg2SO4 + H2O → HgO + Hg + ...
2
votes
1answer
195 views

Why degree of dissociation/ionisation affected by dilution? [closed]

What happens when we dilute, say, an acid which is weak, and then add water to it? What motivates or pushes it to dissociate more? We are just adding some molecules of water, right? So, what exactly ...
2
votes
0answers
171 views

If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium?

If both nitric acid and nitrate ion are stabilised through resonance, what makes the nitrate ion more stable in aqueous medium? Can the same argument be applied to nitrous acid and nitrite ion in ...
1
vote
1answer
46 views

Finding the volume needed to make a new pH

In the titration of 20.00 mL of 0.500 M HCl by 0.500 M NaOH, calculate the volume of 0.500 M NaOH required to reach a pH of 2.0. I have tried to change the 20.00 mL into the amount of substance (0.01 ...
1
vote
1answer
17k views

Is the dissolution of sodium acetate trihydate endothermic?

Sodium acetate trihydrate dissolves in water to its constituent ions: $$\ce{NaOAc.3H2O (s) ->[H2O] Na+ (aq) + OAc- (aq) + 3H2O (l)}$$ The crystallisation of sodium acetate from a supersaturated ...
1
vote
2answers
182 views

Does the amount of solute affect rate of solvation?

I know that in order to increase the rate of solvation, you need to increase how often solute and solvent particles come into contact. You can do it by: agitating the mixture increasing the surface ...
1
vote
2answers
1k views

How can you predict a double displacement reaction with no precipitate?

Is it possible to predict a double displacement reaction between two ions where the products remain in aqueous solution? I see how you can predict precipitation reactions if you know whether the ...
1
vote
2answers
382 views

Why do increasing concentrations of zinc chloride not linearly decrease the freezing point?

I did an experiment on how different concentrations of $\ce{ZnCl2}$ affect the freezing point of demi water. My results were that till a concentration of about $10\ \mathrm{mol\,dm^{-3}}$ the freezing ...
1
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0answers
81 views

What chemicals could be added to human urine to cause harmful chemicals to precipite out?

What chemicals could be added to human urine to render it drinkable with no harmful side effects? Urine is salty and contains other dissolved solids. Thus, drinking untreated urine would result in ...
1
vote
1answer
55 views

How a titration curve is affected when a poorly soluble salt is formed?

Suppose that I have $\pu{100 mL}$ solution of strong acid, $\ce{HA}$, at $\pu{0.10 mol L^{-1}}$. This solution is titrated with a strong base solution, $\ce{BOH}$, at $\pu{0.10 mol L^{-1}}$. Suppose ...
1
vote
1answer
163 views

Why does tetrachlorocuprate(II) form in aqueous solution even though water should be the stronger ligand? [closed]

In aqueous solution, $\ce{Cu^{2+}}$ forms the $\ce{[Cu(H2O)6]^2+}$ complex. Given that water is a stronger ligand than $\ce{Cl-}$, though, why does why does the $\ce{[CuCl4]^2-}$ complex form upon ...
0
votes
1answer
165 views

How to make oil more heavy?

I would like to increase the density of a given oil (or anything that repels water) so that it is slightly heavier than water; to be able to precisely control how slow the oil would fall in the water. ...
0
votes
2answers
302 views

How to reduce surface tension of oil?

I would like to create tiny colored drops slowly falling down in a transparent liquid. The diameter of the droplets must be around 2mm, and their speed must be approximately 0.5 mm / sec. For that, ...
0
votes
2answers
2k views

Confused about strong/weak dibasic and tribasic acids

I know that sulfuric acid is considered a strong acid, and the dissociation of its first $\ce{H+}$ ion is complete and of its second $\ce{H+}$ ion is partial. Phosphoric acid is weak and all three of ...
0
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0answers
45 views

Are these two reactions the same? [duplicate]

I read the book an it said when $\ce{NH4Cl}$ dissolves in the water, the reaction of $\ce{NH4+}$ will be $$\ce{NH4+ <=> NH3 + H+},$$ but instead, the first reaction came to my mind was $$\ce{...
0
votes
1answer
24k views

How to calculate molality, molarity and mole fraction given density (g/mole)?

Calculate the molality, molarity and mole fraction of a $\ce{CuSO4}$ in a 17% m/m aqueous solution (density of the solution is 1.367 g/mole) I did .17 * 1.367 to find grams of $\ce{CuSO4}$ and .83 * ...