Questions tagged [aqueous-solution]
For questions relating to compounds dissolved in water and resulting reactions.
2
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1answer
32 views
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
votes
1answer
23 views
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 ...
0
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1answer
30 views
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 ...
1
vote
1answer
34 views
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, ...
2
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0answers
40 views
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 ...
-1
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1answer
26 views
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, ...
0
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1answer
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.
...
0
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0answers
30 views
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 ...
-2
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0answers
16 views
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/...
1
vote
0answers
26 views
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-}]=...
-1
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3answers
42 views
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 ...
1
vote
2answers
87 views
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 ...
0
votes
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
$$\ce{HC2H3O2 + H2O <=> C2H3O2- + ...
1
vote
2answers
227 views
Calculating solubility of iron(III) hydroxide in water
The following example in Skoog's Analytical Chemistry uses mass-balance and charge-balance equations to calculate the solubility of iron(III) hydroxide in aqueous solution.
$$
\begin{align}
\ce{Fe(...
0
votes
1answer
43 views
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 $\ce{OH-}$ ...
-2
votes
1answer
34 views
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 ...
3
votes
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 $\ce{H+}$ ...
11
votes
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 ...
5
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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
48 views
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).
$$\mathrm{{CO_3}^{2-} + H_2O \ce{<=>} {HCO_3}^- + OH^-} \\
\mathrm{{...
1
vote
1answer
45 views
Dissociation behaviour of polyelectrolytes
Assuming a solution of 100 polycationic molecules, each of them carrying 100 amino groups and an apparent pKa of 6.5. Would it mean that, at a pH of 6.5,
50 molecules will be fully protonated
50 ...
2
votes
1answer
51 views
Why degree of dissociation/ionisation affected by dilution? [closed]
What happens when we dilute, say, an acid which is weak, and then add water to it? What motivates or pushes it to dissociate more?
We are just adding some molecules of water, right? So, what exactly ...
0
votes
2answers
39 views
Is the reaction involving a proton transfer a redox reaction?
$$
\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}
$$
Which of the following statements ...
1
vote
0answers
28 views
What causes the turbidity when preparing Fenton's reagent?
New guy, please be gentle. I might ask questions not according to conventions, I am not a chemist nor do I study chemistry. Feel free to adapt the question and the tagging.
I am preparing a solution ...
0
votes
0answers
36 views
Can a substance be extracted from solution by adding another substance with a higher solubility?
Suppose that I have a substance X dissolved in water. I then add a substance Y to the solution. Substance Y has a higher solubility in water than substance X, and more than enough of substance Y is ...
1
vote
1answer
45 views
Concentration of Hydrogen Ions
I am slightly confused about one certain task.
There are 4 different solutions ($\ce{NH3}$, $\ce{HCl}$, $\ce{NaOH}$, $\ce{CH3COOH}$), their concentration is the same $(c = \pu{1 mol L-1}).$ Which ...
-1
votes
1answer
23 views
Can I have a homogeneous 2 molal solution of copper(II) sulfate at 20 °C?
I'm doing a high school chem project where I am making a calibration curve of copper(II) sulfate for spectrophotometry in which I make solutions with five different concentrations. The most ...
0
votes
3answers
54 views
Solubility and pH
I was reading about antacids. It stated that in earlier times $\ce{NaHCO3}$ and a mixture of aluminium and magnesium hydroxide were used as antacids. In excess $\ce{NaHCO3}$ can make the medium ...
11
votes
2answers
3k views
Would sodium explode in salt water?
I’ve seen the video etc of sodium being put into freshwater and the reaction of flames/small explosion but I wonder if the same reaction would occur if conducted in salt water such as the ocean.
-1
votes
2answers
86 views
Finding mole fraction from molality
Calculate the mole fraction of ammonia in a $\pu{2.00 m}$ solution of $\ce{NH3}$ in water.
What I know is that the formula for mole fraction is
$$X = \frac{\text{no.-of-moles-of-solute}}{\text{(no.-...
1
vote
1answer
43 views
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:
$$\ce{NO3- + 8 e- + 10 H+ → ...
0
votes
0answers
18 views
How to keep magnesium hydroxide suspended in water?
How do I keep 8 g of $\ce{Mg(OH)2}$ suspended in 100 mL of water? Milk of magnesium purchased from the store has $\ce{Mg(OH)2}$ well suspended in the bottles. When I make it, the $\ce{Mg(OH)2}$ ...
8
votes
4answers
884 views
Ionic compound having highest solubility in water
Which ionic compound has highest solubility in water? I can find CsBr having highest solubility with 1230 g/L at 25 °C.
Note: compounds like ethanol are soluble to any extent in water, but they are ...
0
votes
2answers
257 views
Which of the following is the most acidic salt?
A 0.1 M solution of which salt is most acidic?
(a) Aluminum(III) nitrate $\ce{Al(NO3)3}$;
(b) Magnesium(II) bromide $\ce{MgBr2}$;
(c) Sodium bicarbonate $\ce{NaHCO3}$;
(d) Sodium formate $\...
0
votes
1answer
31 views
Evaluate mass of salt needed to add to a buffer solution knowing only pH
This is an exercise taken from an old exam, I'm struggling with the resolution.
To a solution of a generic weak acid $\ce{HA}$ were added $\pu{2.40 g}$ of a potassium salt of the $\ce{KA}$. The ...
1
vote
0answers
28 views
How to make rheoscopic fluid using glycol stearate flakes
Rheoscopic fluid can be made by adding mica powder to water. I read that mica powder can settle and condense after sitting around for a long time. So I want to use glycol stearate flakes instead.
...
0
votes
2answers
57 views
How to balance this redox reaction taking place in a basic medium?
How to balance this reaction which is taking place in a basic medium?
$$\ce{Al + MnO4- -> MnO2 + Al(OH)4-}$$
My Attempt
Reduction half reaction:
$$
\begin{align}
\ce{4 H+ + MnO4- + 3 e- &-&...
1
vote
0answers
23 views
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 ...
0
votes
1answer
34 views
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....
1
vote
1answer
21 views
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 ?
-1
votes
1answer
26 views
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 ...
0
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1answer
48 views
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{...
0
votes
1answer
54 views
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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votes
1answer
27 views
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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votes
2answers
50 views
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
4
votes
1answer
85 views
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 ...
0
votes
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 ...
0
votes
2answers
30 views
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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votes
1answer
73 views
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 ...
2
votes
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 ...
