Questions tagged [aqueous-solution]

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

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0answers
75 views

Conductivity variation on Caustic (NaOH) Dilution System

I am reading the drawing for an automatic caustic dilution system where 50% NaOH is diluted down to 20%. I was expecting to see a density sensor on the outlet to provide feedback to the dilution ...
-2
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1answer
190 views

Molarity of silver(I) nitrate solution after the reaction with magnesium [closed]

$\pu{3 g}$ of $\ce{Mg}$ are placed in $\pu{500 mL}$ of $\pu{0.625 M}$ $\ce{AgNO3}$. When the reaction is complete, what is the molarity of the $\ce{AgNO3}$ solution? I'm thinking you need to use $...
3
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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, ...
2
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0answers
195 views

Varying data about solubility of sodium acetate trihydrate

I recently looked up the solubility of sodium acetate trihydrate in water at 20°C and found surprisingly diverse values such as: 613g/l (GESTIS-Stoffdatenbank) 762g/l (TU Freiberg) 1250g/l (applichem, ...
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0answers
26 views

Potentiometric determination of fluoride

We did an experiment of potentiometric determination of fluoride ions. In several beakers we added several concentrations of NaF solutions and then we added water. We calculated with the electrode the ...
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2answers
615 views

Molality of the solution prepared from a hydrated salt [closed]

A solution is made up by dissolving $\pu{13.8 g}$ $\ce{Na2CO3 · 10 H2O}$ in $\pu{103.5 g}$ of water. What is the molality of $\ce{Na2CO3}$ in this solution? I can't solve it. I tried converting to ...
3
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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
135 views

Weight of sodium acetate required to get to certain pH

How many grams of $\ce{CH3COONa}$ we need to dissolve in $\pu{2.50 L}$ of water to get a solution with $\mathrm{pH} = 9.00$? Given $K_\mathrm{a}(\ce{CH3COOH}) = 1.75\cdot 10^{-5}$ Like solving a ...
5
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1answer
387 views

Does acid and base react directly, or do they react first with water?

If an acid $\ce{AH}$ reacts with a base $\ce{B}$ in aqueous solution, in textbook they write $$\ce{AH + B -> A- + BH+}\label{rxn:1}\tag{1}$$ But first I add acid to water and then base, so why ...
4
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1answer
336 views

Finding equilibrium constant from solubility product constant

Given $$\ce{CuI(s) <=> Cu+(aq) + I-(aq)}\, ;\qquad K_\mathrm{sp} = 1.2 \cdot 10^{-12}$$ write a reasonable chemical reaction that describes the decomposition of $\ce{CuI2}$ in aqueous ...
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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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2answers
12k views

Electrolysis of diluted sulfuric acid

My teacher told me that electrolysis of dil. $\ce{H2SO4}$ (concentration below $50\%$) using inert electrodes results in gradual increase of the concentration of $\ce{H2SO4}$. I can't seem to figure ...
3
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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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1answer
58 views

How do you experimentally calculate the ionization constant of the carbonate ion?

Given sodium hydrogen carbonate, $\ce{NaHCO3}$, as well as hydrochloric acid, $\ce{HCl}$, how would you experimentally determine the ionization constant for the carbonate ion, $\ce{HCO3-}$? By ...
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0answers
356 views

Solubility of Calcium Oxalate in Aqueous Alcohol?

In searching through the literature for the solubility of calcium oxalate, I came across this post https://www.researchgate.net/post/Are_there_any_organic_inorganic_solvents_for_dissolving_Ca-oxalate ...
6
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1answer
102 views

How much additional hydrochloric acid should be added to arrive at ‘excess acid’?

I am an IB student. And I am trying to find the mass percentage of $\ce{NaHCO3}$ in antacid. I am dissolving the antacid in $\pu{0.1 M}$ $\ce{HCl}$ solution. So, first of all I conducted some ...
4
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1answer
79 views

Colloids and Ions

Suppose I have this reaction: $$\ce{3NaOH(aq) + FeCl3(aq) → 3NaCl(aq) + Fe(OH)3}$$ My questions: $\ce{Fe(OH)3}$ doesn't have the (aq) suffix because it isn't separated in water as opposed to $\ce{...
2
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1answer
63 views

Formation of silica from TEOS

Usually tetraethyl orthosilicate/tetraethoxy silane (TEOS) is mixed with both ethanol and water to produce silica in a sol-gel process. I am curious what happens if one adds TEOS to water at a high pH,...
4
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1answer
120 views

A problem in solubility of salts with multistep hydrolysis of an ion possible

Calculate the solubility of $\ce{MnS}$ in pure water, $K_\mathrm{sp}(\ce{MnS}) = \pu{2.5e-10}$. Assume hydrolysis of $\ce{S^2-}$ ion. $K_1$ and $K_2$ for $\ce{H2S}$ are $10^{-7}$ and $10^{-14}$, ...
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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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2answers
635 views

In the blue bottle experiment, will it eventually be “used up” after repeated use?

The blue bottle experiment is a bottle half full of a colorless solution (dextrose, KOH, and methylene blue, in the version that I saw) and air that, when shaken, turns blue through the methylene blue ...
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1answer
51 views

Quantity of water in a redox problem

$\pu{76 g}$ of $\ce{FeSO4}$ are oxidized by $\pu{0.04 M}$ solution of $\ce{KMnO4}$ in presence of $80\%$ $\ce{H2SO4}$. What quantity of water must be added to the final solution of $\ce{Fe2(SO4)3}$ ...
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1answer
114 views

Calculating weight of soluble salt in a solution

I got a solution which density is $\pu{1.035 g mL-1}$ and it contains soluble salt $\ce{Ba(NO3)2}$ at concentration of $\pu{0.250 M}$. The teacher is asking from me to "clear" the solution from the $\...
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2answers
1k views

How to calculate the pH of the neutralisation of HCN with excess of KOH?

Write the reaction between $\pu{0.05 mol}$ $\ce{HCN (aq)}$ and $\pu{0.08 mol}$ $\ce{KOH (aq)}$ with $V = \pu{500 mL}$ and then calculate the pH. So I wrote the reaction: $$\ce{HCN (aq) + KOH (aq) &...
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0answers
49 views

Removing Tungsten Trioxide from Tungsten Electrode

I need a very sharp tungsten electrode, and I think radial electrochemical etching with sodium hydroxide is the way to go. The problem therein (I think) is that the etching will cause an oxide layer ...
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1answer
338 views

Why do the amino groups in EDTA deprotonate first, in contrast to amino acids?

We know that in amino acids, carboxylic acid groups deprotonate first than the amine groups. For example, in alanine, $\mathrm{p}K_\mathrm{a,\ce{COOH}} = 2.34$, $\mathrm{p}K_\mathrm{a,\ce{NH3+}} = 9....
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1answer
2k views

Why does Dead Sea water feel greasy?

The best explanation I found so far is this: These salts (magnesium, potassium, sodium, etc.) are responsible for the "greasy" feel of the water. But it doesn’t say which salts exactly are ...
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1answer
4k views

How do you write the ionization equation for calcium hydroxide?

This is a base that would ionize completely, and the dissociation equation would look like this: $$\ce{Ca(OH)2 <--> Ca^2+ + 2OH-}$$ but how would I write the Brønsted equation with water? $$\ce{...
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0answers
40 views

Should the concentrations in weight % of the components of a solution always add up to 100%?

There's a paper with this statement of a alkaline solution: Nanostructured CuO films were formed by immersing the cleaned tabs into a hot $(\pu{96 \pm 3 ^\circ C})$ alkaline solution composed of $\...
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1answer
5k views

What visual observations can confirm that a reactant is the limiting reagent?

I have this lab question for the lab called Copper Collection Stoichiometry, where we choose an amount of the limiting reagent (iron) for a reaction between copper (II) sulfate and iron. We are to ...
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2answers
763 views

Converting mass percentage of a solution into its density? [closed]

Is there a way of converting mass percentage of a solution to obtain its density? (With mass percentage been given and the compounds which are mixed to form the binary solution)
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1answer
727 views

Why do the Ions Swap in double displacement?

I'm curious but in a double displacement reaction I know that the anions are swapped around and normally a precipitate is formed, but why do the ions swap? Has it got something to do with electrical ...
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1answer
715 views

Why are indicators used only in the form of dilute solutions?

Why are indicators used only in the form of dilute solutions? I get that indicators are a form of weak acids themselves, and the extent of their dissociation varies with the pH of the solution they ...
3
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0answers
484 views

Calculating total volume mixing NaCl and water

I'm (as a non chemist) trying to calculate the the volume of a NaCl solution. The problem is that I know the volume of water prior to mixing in NaCl, but I want to know the volume of the solution ...
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1answer
378 views

So, is baking soda actually a strong base? [duplicate]

Based on my recent thoughts, when baking soda ($\ce{NaHCO3}$) is dissolved in water, the following hydrolysis reaction occurs: $$\ce{NaHCO3 + H2O <=> NaOH + H2CO3}$$ However, $$\ce{H2CO3 -> ...
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0answers
375 views

Is the crystallization process of aqueous solutions of substances such as lithium chloride endothermic?

$\ce{LiCl}$ has an enthalpy of solution of $\pu{-37.1 kJ/mol}$, so its dissolution process is exothermic. Does this mean that it's crystallization process is exothermic? I'm asking since I've looked ...
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1answer
1k views

How to calculate Debye length of a 2-1 electrolyte

I am given the Debye length to be 10nm for 0.001M KCl at 298K. I want to know its Debye length in 0.01M CaCl2. How can this be calculated? I know that for 1-1, the Debye length is inveresely ...
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1answer
2k views

How does adding sodium chloride to a solution of copper sulfate change the equilibrium? [closed]

In school we had a lesson about chemical equilibrium. We performed an experiment: in two tubes we poured $\pu{5 mL}$ of $\ce{H2O}$ and placed $\ce{CuSO4}$, the concentration of the $\ce{CuSO4}$ should ...
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0answers
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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0answers
63 views

Cationic Detergent with no odor [closed]

I am looking for a cationic detergent for a project. Unfortunately most ( or all?) cationic detergents are quaternary ammonium that smell like rotten fish or even worse The product I am working on ...
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2answers
881 views

How to calculate the concentration of the elements after dissolution of iron(III) chloride?

I was presented with the following problem: In the laboratory you dissolve $\pu{24.7 g}$ of iron(III) chloride in a volumetric flask in water to a total volume of $\pu{375 ml}$. What is ...
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1answer
538 views

What are the dangers associated with a copper sulfate CuSO4 + Water H2O solution aprox 5 gallons at room temperature in a room with no ventilation.

Will there be hazardous gases in the room? is the evaporation of this solution harmful in any way to animals or humans?
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0answers
240 views

What determines the maximum size of salt crystals as grown in flux growth?

Like many other children, I grew single crystal salt crystals in a salt solution. This is a common and fun experiment for children. However, with both this experiment, and with flux growth methods ...
2
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6answers
5k views

Why is the specific gravity of 0.9 % saline 1.0046?

Medical Normal Saline (0.9% Saline) contains 9 g of salt dissolved in 1000ml of water. Hence a litre of NS should weigh 1.009 kg. Hence its specific gravity should be 1.009, but it’s only 1.0046. (I'...
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2answers
3k views

Solubility of Alkali Metal Chlorides

Why does Potassium Chloride less soluble than Sodium Chloride in water, isn't it supposed to be other way round? Since Potassium Chloride would be more ionic than Sodium Chloride?
4
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1answer
882 views

Why isn't the hydroxyl group of citric acid deprotonated while the carboxyl groups are?

My AP chemistry book "Chemistry: the Central Science 12th edition" says that one molecule of citric acid generates 3 H+(aq) ions when dissolved in water. Looking at the structural formula: There are ...
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0answers
114 views

Can a used-up buffer solution be used again in the other direction?

Suppose a strong base is added into an acidic buffer (such as acetic acid buffer) up to the endpoint. This means that the acetic acid molecules neutralize the hydroxide ions to the point that the ...
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0answers
51 views

Why does soapy dishwater lose soapiness over time?

I wash dishes by making a concentrated solution of dishsoap (eg dawn) and water. Sometimes I'm lazy and forget to wash the container containing the soap solution, and it sits on the counter overnight....
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1answer
421 views

Propylene Glycol as a water main anti-freeze

We are a young student science group looking for solutions to real world problems. We are currently working on ways to keep our city water mains from freezing in the winter. Our team is researching ...
2
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2answers
672 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(...