Questions tagged [aqueous-solution]

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

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Solubility of PbSO4

The solubility of $\ce{PbSO4(s)}$ increase with the addition of $\ce{H2SO4}.$ Why? I don't quite understand this. When dissolving $\ce{PbSO4(s)}$ we get the equilibrium equation: $$\ce{PbSO4(s) <=...
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3k views

Why does saline have a pH of 5.5?

I am a physician and administer 0.9% NaCl in water ("normal saline") to patients frequently. The bag says it has a pH of 5.5 (compared to the human body of 7.4). I am asking why the pH is so low. It ...
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115 views

How can copper(II) sulfate crystallize outside a glass vial?

I'm making copper sulfate crystals in glasses. Within a few weeks, the copper sulfate seems to crystallize both inside and outside the glass: (A few weeks after making a new solution) (Yet another ...
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157 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 ...
4
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2answers
261 views

Does the salinity in seawater affect the process of alkaline hydrolysis?

I am an architecture student doing a project on crematorium spaces. I am looking at resomation or alkaline hydrolysis as an alternative method of disposition of a body. From what I gather from ...
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1k views

How to break down soap and detergents?

I am building a greywater harvesting system. It is a 3-stage system: The 1st stage breaks down soap and detergents. The 2nd stage filters the water. The 3rd stage pumps water out of system. What ...
4
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2answers
151 views

What is the minimum pressure for existence of a liquid solution?

The minimum pressure for the existence of liquid solution is $0.6\;\mathrm{atm}$ $0.8\;\mathrm{atm}$ $0.77\;\mathrm{atm}$ $0.9\;\mathrm{atm}$ Although this seems to be an informative question, I ...
3
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3answers
442 views

What is the compound called when it is in solution?

When a compound precipitates out of solution, for example Calcium Carbonate from a water solution, it is called the precipitate. What is the same compound called before it precipitates out - once it ...
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2answers
6k 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 ...
3
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3answers
574 views

Why does dissolving a salt in water get a high pH?

I dissolved some sodium carbonate in water and I measured the $\mathrm{pH}$. It turned out to be 11. I don't really understand why dissolving it in water increased the $\mathrm{pH}$. I mean, I know ...
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4answers
21k views

Difference between precipitation and crystallisation

What is the main difference between precipitation and crystallization. Is precipitation a chemical change and crystallization a physical change. How can we say that the resulting solute is precipitate ...
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2answers
961 views

How to dissolve white dextrin in water?

Dextrin is labelled as highly soluble in water. I have white dextrin (analytical from Sigma Aldrich). When I mix it in water, no matter how long I stir and how little dextrin I put, I get a suspension....
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2answers
51 views

Precipitating silver(I) salts from the solution of barium(II) cyanate and iodide

Consider a $\pu{10.0 mL}$ solution containing $\pu{1.0e-10 M}$ each of $\ce{Ba(CN)2}$ and $\ce{BaI2}$. If $\pu{3.5e-9 mol}$ of $\ce{AgNO3(s)}$ is added to this solution, will any precipitate(s) form? ...
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511 views

What does the hydrolysis of a salt tell us about its basic/acidic character?

I'm curious to know how basicity and acidity arises when a salt or covalent compound is dissolved in water.
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2answers
178 views

Would dissolving a salt and letting it sit for 48 hours have an effect on the solution?

If one were to dissolve magnesium citrate (about $100~\mathrm{mg}$) in water (about $70~\mathrm{ml}$) and let the solution sit for 48 hours, would the solution be exactly the same as one dissolved and ...
3
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2answers
288 views

Is Fe(OH)2 soluble in alkalis?

I have just started inorganic chemistry in school and I have just learnt about metal aqua ions and how they react in water. I learnt that $\ce{[Fe(H2O)6]^2+}$ reacts in water by losing a $\ce{H+}$ ...
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1answer
1k views

Which is more soluble in water, HF or SO2?

I was wondering which is more soluble in water, hydrogen fluoride or sulfur dioxide? Since $\ce{HF}$ will hydrogen bond to other HF particles (as opposed to $\ce{SO2}$ dipole-dipole attraction). ...
3
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2answers
480 views

How might one reduce the concentration of bubbles in their ice, from ice cube trays?

So I have been freezing ice a lot recently, and I will come out and say it, as it turns out it is, albeit unlikely, it is sometimes possible for ice to "explode." I was not so aware of this before, ...
3
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2answers
224 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 $\...
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1answer
113 views

Adding ethanol to louche

I'm watching MIT chemistry by Donald Sadoway. In one of his lectures devoted to solutions and phase separation, he performs experiments with absinthe. First he mixes absinthe with 5 $\times$ water ...
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2answers
10k views

Why bother to standardize a solution?

I have been preparing lessons for some of my students about preparing acidic and basic solutions, and I keep finding pre-made labs in which the students "standardize a basic solution" by titrating it ...
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2answers
3k views

Why did my iron nails not dissolve in hydrochloric acid?

I was trying to dissolve iron metal in HCl to make iron chloride, but ran into some problems. I'll give a brief background of my experiment. I took iron nails and put them in a container filled with ...
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1answer
7k views

The solubility of different compounds relative to each other in water

Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. It is measured in terms of the maximum amount of solute dissolved in a solvent ...
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2answers
2k views

Mass of salt required to make a 1.2 g/ml solution

I would like to make an NaCl and water solution with a density of 1.2 g/ml. How would you calculate the grams of NaCl required to make a 1000 ml solution? I have used density of mixture = (mass NaCl +...
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2answers
7k views

Why do acids ionize in solution if they are covalently bonded?

Maybe I am wrong, but I thought acids were covalently bonded since hydrogen doesn't form ionic compounds. For example, wouldn't $\ce{HCl}$ look like: Since the electrons are shared, why does it ...
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2answers
79 views

How to measure quantities at standard state when this state is a hypothetical one?

Consider the reaction $$\ce{A(g) + H2O(l) <=> B(aq) + C(g)}$$ If all gases and solutions were ideal, the standard state would be pure water, the solute B at a concentration of 1 M, the gases A ...
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1answer
254 views

Does aniline breakdown in groundwater produce benzene

Can the benzene ring attached to aniline be detached in an aqueous solution (specifically groundwater) under certain conditions? Would the two compounds be detected as separate entities in a ...
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2answers
12k views

Caffeine dissolution

I am looking to add caffeine powder in pure form to water that has a pH level of 7 or higher. What would the pH level be if I do this? Is Caffeine itself acidic?
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3answers
1k views

What is the procedure to create stock solutions?

Until now to execute this recipe, each time i had to count those milligrams/Liter. An enough difficult procedure. I am posting here this question to help me understand the procedure of creating ...
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2answers
6k views

Stability of transition metals in aqueous solution

Which is more stable in aqueous solution: $\ce{Cr^3+}$ or $\ce{Mn^3+}$? Why? My approach: $\ce{Cr^{3+}}$ should be more stable as the $\ce{3d}$ electrons will enter the $\mathrm{t_{2g}}$ orbitals. ...
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3answers
1k views

Are refractive or density based Brix meters better for use with alcoholic drinks?

Assume that somebody wants to measure the sugar content of a liqueur. It seems that there are two types of Brix meters for it, ones which use the solution density and ones which use refraction of ...
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1answer
2k views

Notation “5% solution”

What does 5% aqueous solution of glucose mean? Note that it's just 5% and not 5%w/w. Do we assume it to be w/w? The question is If the osmotic pressure of 5% aqueous soultion of glucose is $\pi_1$...
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2answers
3k views

Why doesn't water play a role in reactions in aqueous reactions?

$$\ce{Ba(NO3)2(aq) + Na2CO3(aq)}$$ In the above reaction both the substances are in water, however water plays no role in the reaction. Why is it that although water is present in the reaction, it ...
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1answer
667 views

USNCO question - Finding pH of salt solution from pKa of its parent acid

The question from 2017 USNCO is as below: What is the $\mathrm{pH}$ of a $\pu{0.25 M}$ solution of $\ce{NaCN}$? (The $\mathrm{p}K_\mathrm{a}$ of $\ce{HCN}$ is $9.21$.) (A) $4.91$ (B) $8.61$ ...
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2answers
9k views

Solution for storing a glass electrode

What kind of storage solution is required for a glass electrode? Is 3 M $\ce{KCl}$ sufficient for this purpose? If so, what is the approximate pH of that solution (the solution I use presently has a ...
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2answers
7k views

About pH of an aqueous solution of SO2

Probably we can have an aqueous solution of $\ce{SO2}$ by dissolving it in water, because we would have an equilibrium between $\ce{SO2(g)}$ and $\ce{SO2(aq)}$: $$\ce{SO2(g) <=> SO2(aq)}$$ How ...
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2answers
2k views

Can artificial sea water be prepared by mixing sea salt with water?

I am looking for ways to easily prepare artificial sea water. The chemical composition doesn't have to exactly match that of natural sea water. On-line I can find recipes to prepare sea water. But I ...
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2answers
4k views

How to calculate the solubility product for PbS from galvanic potential?

Knowing that at 25 °C the following galvanic cell: $$\ce{Pb~|~Pb(NO_3)_2~1M~||~PbS~saturated~|~Pb}$$ shows an $\mathrm{EMF} =0.413~\mathrm{V}$, find the $K_\mathrm{sp}$ of $\ce{PbS}$. My Approach ...
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2answers
3k views

Heat when dissolving solutes in water

Why do certain solutes dissolved in water release heat and other solutes absorb heat?
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2answers
9k views

Can two precipitates form in a precipitation reaction that starts with only two compounds in water? [closed]

Can two precipitates form in a precipitation reaction that starts with only two compounds in water?
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1answer
93 views

Flaw in my logic on Henry's Law?

It states mathematically $ p=Kx $ where $x$ is mole fraction of dissolved gas and $p$ is partial pressure of the gas. Dissolution of gases is exothermic, so with increase in temperature, solubility $x$...
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1answer
72 views

Using cryptands to make a negatively-charged solution?

In our discussion group, my friend mentioned that metal cations can be separated from other cations in solution using cryptands. After addition of the cryptands to the solution of the cations, ...
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2answers
480 views

How to calculate molarity and the number of molecules for a mixture in a simulation box?

I want to do a simulation of a mixture which consists a total of $512$ molecules of glycine, ammonia, and water molecules mixture in a cubic box of, say, length $\pu{2.6 nm}$; $\pu{2.6 nm}^3 = \pu{17....
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1answer
520 views

Change in volume of two beakers on reaching equilibrium

Two beakers are placed side by side in a sealed container. The first beaker contains 100 ml of pure water. The other an equal volume of an aqueous solution of sugar. What should be the volume of the ...
3
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1answer
2k views

Can silver metal be used to electrochemically reduce copper?

I have a solution of copper(II) ions and several cations. I am trying to reduce the copper ions to copper metal with electricity. My Ideas was to use silver as the anode and a copper wire as the ...
3
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1answer
86 views

What could cause one brand of carbonated water to be superiorly carbonated compared to another?

I buy a lot of carbonated water, its pretty much all I drink. There is something I've noticed that just made me curious though. The usual brand I buy is the cheapest one available, 14 cents per 1,5l. ...
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1answer
1k views

How to minimise solution concentration changes due to evaporation?

Lets say I have a precise solution, and would like to store it long term (up to two years) with as little as possible change in concentration. The volume is 10-100ml. What container should I choose? ...
3
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1answer
583 views

Predicting pH of an acidic salt of an weak acid and weak base

Suppose we want to calculate pH of an $\ce{NH4HCO3}$ solution of known concentration. Now, $\ce{NH4+}$ will be hydrolised to give $\ce{H+}$ ions. Some $\ce{HCO3-}$ ions will be converted to (i) $\ce{...
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2answers
1k views

Carbonic acid-hydrogencarbonate buffer system pH calculation?

I am learning about the pH of buffer solutions, and am slightly confused by my text book's calculation. For the blood's buffer system of carbonic acid and hydrogencarbonate ions as the conjugate case, ...
3
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1answer
103 views

Why don't water molecules react alongside aqueous reactions?

To explain my question I'll use an example: We all know that sodium displaces copper in a solution of its sulfate in the reaction: $$\ce{2Na (s) + CuSO4 (aq) \rightarrow Na2SO4 (aq) + Cu (s)}$$ My ...