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Questions tagged [aqueous-solution]

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

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How to take a sample of a hot salt solution without it precipitating in the cooler glassware due to the difference in solubilities at different temps?

I'm doing an investigation to see the effect of temperature on the solubility product of strontium hydroxide. I made a supersaturated solution left in the oven overnight at 85°C for equilibrium to be ...
2
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1answer
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How does monoethanolamine (MEA) increase pH?

I know pH of a solution increases with increase concentration of $\ce{OH-}$. I'm wondering: when adding MEA, is the $\ce{OH-}$ group from the MEA breaking off, or is it the whole MEA molecule taking ...
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1answer
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Reactions between Ca(OH)2 and CO2, and Sr(OH)2 and CO2

So I'm doing an investigation, and it involves using supersaturated solutions of Ca(OH)2 and of Sr(OH)2. I notice that there's always a flaky precipitate formed on top. I need to know about the ...
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1answer
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Identifying Lewis acid

What is the Lewis acid on the reactants side? $$\ce{HNO2(aq) + HPO4^{2-}(aq) <=> NO2-(aq) + H2PO4-(aq)}$$ The book says it is the $\ce{H+}$ only, not the whole molecule of the nitrous acid, ...
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Mechanism for removal of pesticides from fruit by sodium bicarbonate

When Googling around for methods to remove pesticides from fruits and vegetables, a study commonly referred to from some news sites (e.g. here and here ) is one where soaking apples in a sodium ...
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1answer
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Polyprotic Acid Titrations

Titrating a mixture of strong and weak acids will yield endpoints such that the volume of base required to reach each endpoint will be different for each acid, e.g. in a mixture of HCl and CH3COOH, ...
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34 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. ...
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Qualitative analysis of iron(III) salt

Why will $\ce{Fe^3+}$ give brown ring test? In my textbook it was given that ferric ion gives brown ring too. I am confused, if ferric ion is already present, then what will reduce nitrate ion to ...
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10% W/w solution

I need to make a 100mL, 10% w/w solution of 30% ammonia solution & water. The density of my 30% ammonia solution is 0.89g/mL. The density of water is 1g/mL. My calculations are as follows: 10g/...
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how can I predict the rate of water ions precipitation on a surface?

Consider a titanium pot that contains 1kg water with the following ions: $[Ca^{2+}]=22000$ ppm, $[Mg^{2+}]=1500$ ppm,$[Sr^{2+}]=791$ ppm,$[Na^{1+}]=48000$ ppm,$[Cl^{1-}]=120000$ ppm,$[SO_4^{2-}]=...
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An aqueous solution of NaCl has a mole fraction of 0.21. What is the mass of NaCl dissolved in 100.0 mL of solution? [closed]

Work mole fraction of NaCl = 0.21/0.21+0.79 If there is 1 mol of total solution, there will be 0.21 mol NaCl and 0.79 mol H2O 0.21 mol NaCl = 12.27 g 0.79 mol H2O = 14.23 g this would yield a ...
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How much of Ag has formed on the Cu tile?

$\pu{9.547 g}$ $\ce{Cu}$ tile is added to an $\ce{AgNO3}$ solution. After some time, $\ce{Cu}$ was taken out of the solution, washed, dried and weighed. The mass appeared to be $\pu{9.983 g}$. How ...
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1answer
45 views

Equilibrium constant for the neutralization of weak acid by strong base

Acetic acid has a $K_\mathrm{a}$ of $\pu{1.8e-5}$. What is the equilibrium constant for the neutralization of this acid with $\ce{NaOH}$? Given acetic acid $$\ce{HC2H3O2 + H2O <=> C2H3O2- + ...
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2answers
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Calculating solubility of iron(III) hydroxide in water

The following example in Skoog's Analytical Chemistry uses mass-balance and charge-balance equations to calculate the solubility of iron(III) hydroxide in aqueous solution. $$ \begin{align} \ce{Fe(...
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1answer
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Why this redox equation occurs on basic medium?

I have the following redox equation that I need to balance: $$\ce{MnO4-(aq) + SO3^2-(aq) → MnO2(s) + SO4^2-(aq)}$$ The problem says that it happens on basic medium, but I don't see the $\ce{OH-}$ ...
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1answer
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How do I get a 20% ratio of sodium bisulfate with 1 gallon water? [closed]

How many lbs do I add to 1 gallon of water to get a 20% sodium bisulfate ratio? I am in the middle of anodizing some aluminum.... I just threw the whole 3 lbs in... hopefully it works... I ended up ...
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2answers
142 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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4answers
257 views

Is there any electronic component to water conductivity?

Answers to Decrease in temperature of a aqueous salt solution decreases conductivity indicate that the electrical conductivity of salt solutions arises from the mobility of ionic species and therefore ...
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2answers
277 views

Decrease in temperature of a aqueous salt solution decreases conductivity

Why does the conductivity of a water solution drop as the temperature decreases? How are these two related?
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1answer
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Acidity of carbonate ions creates paradox?

Whilst I understand why salts can be acidic or basic, the carbonate reaction confuses me (carbonate being a basic ion). $$\mathrm{{CO_3}^{2-} + H_2O \ce{<=>} {HCO_3}^- + OH^-} \\ \mathrm{{...
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1answer
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Dissociation behaviour of polyelectrolytes

Assuming a solution of 100 polycationic molecules, each of them carrying 100 amino groups and an apparent pKa of 6.5. Would it mean that, at a pH of 6.5, 50 molecules will be fully protonated 50 ...
2
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1answer
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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 ...
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2answers
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Is the reaction involving a proton transfer a redox reaction?

$$ \begin{align} \ce{H2S (aq) + NH3 (aq) &→ NH4+ (aq) + HS- (aq)}\tag{1}\\ \ce{Pb(s) + 2 FeCl3 (aq) &→ 2FeCl2 (aq) + PbCl2 (aq)}\tag{2} \end{align} $$ Which of the following statements ...
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0answers
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What causes the turbidity when preparing Fenton's reagent?

New guy, please be gentle. I might ask questions not according to conventions, I am not a chemist nor do I study chemistry. Feel free to adapt the question and the tagging. I am preparing a solution ...
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0answers
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Can a substance be extracted from solution by adding another substance with a higher solubility?

Suppose that I have a substance X dissolved in water. I then add a substance Y to the solution. Substance Y has a higher solubility in water than substance X, and more than enough of substance Y is ...
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1answer
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Concentration of Hydrogen Ions

I am slightly confused about one certain task. There are 4 different solutions ($\ce{NH3}$, $\ce{HCl}$, $\ce{NaOH}$, $\ce{CH3COOH}$), their concentration is the same $(c = \pu{1 mol L-1}).$ Which ...
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1answer
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Can I have a homogeneous 2 molal solution of copper(II) sulfate at 20 °C?

I'm doing a high school chem project where I am making a calibration curve of copper(II) sulfate for spectrophotometry in which I make solutions with five different concentrations. The most ...
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3answers
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Solubility and pH

I was reading about antacids. It stated that in earlier times $\ce{NaHCO3}$ and a mixture of aluminium and magnesium hydroxide were used as antacids. In excess $\ce{NaHCO3}$ can make the medium ...
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2answers
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Would sodium explode in salt water?

I’ve seen the video etc of sodium being put into freshwater and the reaction of flames/small explosion but I wonder if the same reaction would occur if conducted in salt water such as the ocean.
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Finding mole fraction from molality

Calculate the mole fraction of ammonia in a $\pu{2.00 m}$ solution of $\ce{NH3}$ in water. What I know is that the formula for mole fraction is $$X = \frac{\text{no.-of-moles-of-solute}}{\text{(no.-...
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1answer
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Why is water instead of hydroxide ions used to balance oxygen atoms in redox half equations?

When balancing half equations of redox reactions, $\ce{H2O}$ is used to balance any oxygen atoms? For example, this half equation $$\ce{NO3- → NH4+}$$ is balanced into: $$\ce{NO3- + 8 e- + 10 H+ → ...
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0answers
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How to keep magnesium hydroxide suspended in water?

How do I keep 8 g of $\ce{Mg(OH)2}$ suspended in 100 mL of water? Milk of magnesium purchased from the store has $\ce{Mg(OH)2}$ well suspended in the bottles. When I make it, the $\ce{Mg(OH)2}$ ...
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4answers
884 views

Ionic compound having highest solubility in water

Which ionic compound has highest solubility in water? I can find CsBr having highest solubility with 1230 g/L at 25 °C. Note: compounds like ethanol are soluble to any extent in water, but they are ...
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2answers
257 views

Which of the following is the most acidic salt?

A 0.1 M solution of which salt is most acidic? (a) Aluminum(III) nitrate $\ce{Al(NO3)3}$; (b) Magnesium(II) bromide $\ce{MgBr2}$; (c) Sodium bicarbonate $\ce{NaHCO3}$; (d) Sodium formate $\...
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1answer
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Evaluate mass of salt needed to add to a buffer solution knowing only pH

This is an exercise taken from an old exam, I'm struggling with the resolution. To a solution of a generic weak acid $\ce{HA}$ were added $\pu{2.40 g}$ of a potassium salt of the $\ce{KA}$. The ...
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How to make rheoscopic fluid using glycol stearate flakes

Rheoscopic fluid can be made by adding mica powder to water. I read that mica powder can settle and condense after sitting around for a long time. So I want to use glycol stearate flakes instead. ...
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2answers
57 views

How to balance this redox reaction taking place in a basic medium?

How to balance this reaction which is taking place in a basic medium? $$\ce{Al + MnO4- -> MnO2 + Al(OH)4-}$$ My Attempt Reduction half reaction: $$ \begin{align} \ce{4 H+ + MnO4- + 3 e- &-&...
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0answers
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Dependence of Osmotic Effects on Particle Size

van't Hof's equation for osmotic pressure is derived with the assumption, among others, that the particle size of the solute is comparable to the particles size of the solvent. It holds well so long ...
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1answer
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Is the water in an aqueous solution undergoing a reaction considered part of the system or surroundings?

System: In chemistry, a system is a chemical reaction. A system operates within its surroundings. Energy can move between the two. Surroundings: The environment around a particular chemical reaction....
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1answer
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Gas solution - State of matter

When a gas is dissolved in water does the state of gas changes ? We write it as aqueous but what is the state that exists ? does it has the properties of gases when it is dilluted ?
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1answer
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How can I get create complex metal ion solution such that the majority of the central metal ions only have one specific ligand?

I'm looking for a way to have the ligand, Chloride ion, datively bond with Copper Sulphate. I understand it is as simple as creating a solution of Hydrochloric Acid and dissolving Copper Sulphate ...
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1answer
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Does electrolysis of aqueous tin (II) chloride produce Cl2 or SnCl4? Or both?

When applying a current to an aqueous solution of tin (II) chloride, tin crystals grow from the cathode. However, I'm not sure about the anode. It seems like there are two possible reactions: $$\ce{...
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1answer
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The density of an aqueous solution

Could the density of an aqueous solution be less than 1g/ml ? For an example, can 0.98g/ml be taken as a density for an aqueous sulphuric acid solution ?
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1answer
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Quantity of base needed to neutralise litre of 36% HCl?

Sorry for asking a basic chemistry question. I last did this kind of chemistry at school about 30 years ago and I don't have confidence that I'd get it right from first principles :) Short version: ...
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Every liquid is water [closed]

Is it that every liquid we see is water, with more or less of x substance? Example: urine is water with salt and minerals
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1answer
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What component(s) of instant coffee make it deliquescent?

If I put small, separate piles of instant black coffee powder, sugar, powdered creamer, and even something very ionic like table salt out in humid air and come back in a few days, only the instant ...
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1answer
209 views

Why do nonmetal oxides react with water to form acidic compounds? [closed]

I am confused about the molecular basis by which nonmetal oxides react with water to form acidic compounds. For example, I understand that sulfur trioxide reacts with water to form sulfuric acid as ...
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2answers
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Why don't ions form crystal lattices in water and other polar solvents?

Ionic compounds are in the form of crystal lattices, and when they are dissolved in a polar solvent, they are bonded with the corresponding cations/anions of the polar solvent. For example, $Na^+$ ...
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1answer
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Advice on forming a 10% solution of Maltol

I’m having great trouble forming a 10% solution of Maltol. Specifically, I’m trying to dissolve 3 grams of Maltol in 27 grams of solvent. I’ve tried everything from Propylene Glycol, to Deionized ...
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1answer
238 views

Diluting methanol in water: is it exothermic?

Can someone explain in simple terms why does temperature increase when mixing water with methanol? I do not have a strong background in chemistry, but I usually have to mix both liquids (sometimes ...