Questions tagged [solutions]
This tag should be applied to questions dealing with solutions of any kind. A solution is a liquid or solid phase containing more than one substance where, for convenience, one (or more) substance(s) called the solvent is treated differently from the other substances, which are called solutes. If water is the solvent, then the more appropriate 'aqueous-solution' tag should (also) be specified.
972
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Copper anode dissolves in electrolysis of copper sulfate solution [closed]
I did an experiment with copper sulfate where you place two copper rods in an aqueous solution of copper sulfate. You apply an electric current and copper metal builds up on the cathode. I noticed ...
7
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3
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What does washing and drying a solution mean?
After combining two solutions, a direction in a 1970s British chemistry book says to wash the new solution with a mixture of baking soda, table salt, and water. Then it says to dry it with anhydrous ...
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3
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2
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755
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How does a shock, such as the snap of the disk in a reusable hand warmer, trigger the re-crystalization of a supersaturated solution?
Reusable handwarmers are made of something dissolved nearly to its saturation point in hot water (Sodium Acetate in the case of HotSnapz) at a high temperature, and then cooled to a temperature at ...
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1
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What is the temperature needed for a reflux using a mix of solvents as the reaction medium? [closed]
I had a quick query regarding the setup of a reaction. The procedure that I am working from states that I need to put my reaction mixture under reflux for 3 hours. The solvents used are diethyl ether (...
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3
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859
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Detailed kinetic explanation for vapor pressure reduction by dissolved solute?
The following problem was asked in JEE Mains 2020 (Sept 2, Shift 1),
An open beaker of water in equilibrium with water vapor is in a sealed container. When a few grams of glucose are added to the ...
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1
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804
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Who came up with C1V1 = C2V2? [closed]
I was wondering if there is an original scientific publication showing why $C_1V_1 = C_2V_2$ works.
Or perhaps, who described/used it first?
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42
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Solubility Product, and it's relation to solubility
In order to remove temporary hardness of water, it is boiled.
On boiling, while Ca(HCO3)2 gives CaCo3(ppt.) , Mg(HCO3)2 gives Mg(OH)2(ppt.).
According to my book precipitation of Mg(OH)2 occurs due to ...
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204
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Is sulfuric acid necessary for Kevlar synthesis?
In the production of Kevlar, the 2 monomers needed for its creation are reacted in a solution. Due to it being water-insoluble, sulfuric acid is used. My question: Can other chemicals be used as well (...
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1
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63
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Actual color of colloids [closed]
I have read that the color of colloid depends upon the wavelength of light scattered by the dispersed phase and also in the sense in which the receiver receives the light.
If all of this depends on ...
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1
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0
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460
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Freezing point of solution of Water, Ethanol and Sugar (aka, Limoncello)
I'm looking for a diagram of the freezing point of a water solution depending on its content in sugar and ethanol. More colloquially, I want to know how to balance alcohol and sugar so that my ...
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1
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174
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Find volume of ammonia gas required to prepare a solution of given pH [closed]
Calculate the volume of gaseous ammonia $(K_\mathrm{b} = \pu{1.8E-5})$ to dissolve (at NTP) in $\pu{100 mL}$ of water in order to obtain a solution with $\mathrm{pH} = 11.0.$ Consider volume variation ...
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1
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302
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Ionisation vs Dissociation
This is a statement given in my book:
A strong electrolyte is completely ionised at all dilutions but not completely dissociated.
But the book also uses the terms "Ionisation" and "...
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2
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Can aluminium form blue-colored solution in liquid ammonia?
I've read that group 1 elements and group 2 elements with exception of Be form blue-colored solutions in liquid ammonia (Mg requires an electrolytic process). What are the conditions for a metal to ...
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What is vacuum-assisted ultrasonication?
This quote from a methods section of a paper:
[samples were] ultrasonicated for approximately 30 min to ensure
adequate dispersion of the components throughout the mixture. The
solution was then ...
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1
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91
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Extrema in free energy of a solution?
I am a high school student reading about the second law of thermodynamics, and one of the equations given was the free energy change in dilution.
$$\Delta G_{\text{dil}} = -RT \log(C_1/C_2)$$
This ...
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1
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Why sugar solution/sugarcane juice becomes sour when kept for certain time?
I stir-dissolve some sugar in a cup of water and then keep it open for certain time (say a few hours), when I taste it I feel that it has became sour.
I have observed the same thing many times when I ...
0
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1
answer
109
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Molality of solution to be used when finding water separated from solution as ice
Question
$\pu{1 kg}$ of a solution of cane sugar is cooled and maintained at $\pu{-4 ^\circ C}$. How much ice will separate out if molality of solution is $0.75$?
$K_\mathrm{f} \ \text{(water)} = 1....
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1
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How is the formula of mean activity coefficient derived?
The mean activity coefficient is defiend as follows:
$$\gamma_\pm = (\gamma_+\gamma_-)^{1/2}.\tag{1}$$
If Debye-Hückel equation
$$-\log\gamma_i = 0.5z_i^2\mu^{1/2}\tag{2}$$
is used, then the mean ...
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0
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57
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Solubility of salts in water
I came across the formula for enthalpy of solution, which is equal to the sum of lattice enthalpy and hydration enthalpy. Therefore, for salts that have endothermic dissolution, the lattice enthalpy ...
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1
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1
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166
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Are colligative properties applicable for volatile liquids and gases in liquid solvent? Why/Why not?
My teacher told me that the expressions for calculation of colligative properties like lowering in freezing point are only applicable if the solute is non volatile liquid or a solid. We cannot apply ...
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1
answer
69
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Caustic and Toxicological Determination [closed]
I need to determine whether or not a product that I am importing is "toxic" and or "corrosive" as defined below. But I am a chemistry n00b — that is to say I have virtually zero ...
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3
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1
answer
858
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At what composition is Maximum deviation from Raoult's law observed?
Raoult's law states that in an ideal binary solution of two volatile components, the partial vapour pressure of each component is proportional to its mole fraction in the solution.
A plot of total ...
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10
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2
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Limitations of Henry's law
Consider the diagram
Henry's law is a gas law that states that the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid. The proportionality factor is called ...
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1
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865
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Do pipettes always outclass glass syringes?
I was previously working in a lab preparing lots of samples for gas chromatography that exclusively used glass pipettes and was able to get really high precision between replicates. Now I'm working on ...
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1
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232
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How does sodium rosinate enhances lathering property? [closed]
Why don't we use sodium carbonate or sodium stearate? What does sodium rosinate contain that the other two don't?
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0
answers
39
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Column Dispersive Mass Balance analytical / numerical solution
Is there any analytical solution for the most common expression of column mass balance:
$\dfrac{\partial C}{\partial t} + \left(\dfrac{1+\varepsilon}{\varepsilon}\right)\dfrac{\partial q} {\partial t} ...
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2
votes
0
answers
74
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Understanding formulas for PZT
In the slides i'm studying (about the production of PZT), is given the following formula for lead zirconate titanate :
$$\ce{PbZr(Ti)O_3}$$
with the explanation:
It is a solid solution of two oxides: ...
3
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1
answer
185
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Is the mole fraction used in Raoult's law calculated initially or at equilibrium?
Raoult’s law states that:
The partial pressure of any volatile constituent of a solution at a constant temperature is equal to the vapour pressure of pure constituent multiplied by the mole fraction ...
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0
votes
2
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158
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Definition of “solution” [closed]
In my textbook “solutions” are defined as follows:
Homogenous mixtures of two or more substances are known as solutions.
Should the two substances always be non-reacting?
The definition has no ...
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3
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2
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140
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How can one reclaim isotopic cadmium from a solution of acid, i.e. H2SO4 or HCl etc.?
I have dissolved isotopic cadmium-114 with $\ce{H2SO4}$ and or $\ce{HCl}$. Now that I have the cadmium-114 in solution, precipitating out $\ce{CdSO4}$ and or $\ce{CdCl2}$, how can I reduce these ...
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4
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477
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How many grams of sodium phosphate must be added to precipitate as much of one ion as possible?
Problem text:
Solid sodium phosphate is slowly added to $\pu{200 mL}$ of a solution containing $\pu{0.002 mol}$ of aluminum chloride and $\pu{0.001 mol}$ of calcium chloride (assuming no volume ...
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1
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1
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Using solubility product to determine the mass of the precipitate of a reaction
I mix together $\pu{100 mL}$ of an aqueous $\ce{NaCl}$ solution at $\pu{0.5 M}$ and $\pu{100 mL}$ of an aqueous $\ce{AgNO3}$ solution at $\pu{0.3 M}$. Assuming that the solubility of $\ce{NaCl}$ in ...
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1
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Creating a chemical solution with water and chlorine
I bought a swimming pool for my kids and also a measurement instrument for measuring the amount of chlorine in the pool in mg/l. The problem is now that you have to calibrate the instrument before ...
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1
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110
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Radioactive decay of ions in solution [closed]
What happens when ionic salts in solution decays? For example, if I had a handful of Francium-223 Palmitate(Francium salt of palmitic acid) and I were to put it in solution, how would the francium ...
0
votes
1
answer
106
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Calculating concentration of OH⁻ ions [closed]
Calculate concentration of $\ce{OH-}$ ions in $\pu{0.66 mol L^-1}$ solution of $\ce{NH4+}.$
I think that there might be something missing, as the only law I have for this kind of problems is
$$[\ce{...
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votes
1
answer
215
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Deviations from Raoult's Law [closed]
A solution of two compounds may be an ideal solution and follow Raoult's Law, or it may show a positive or negative deviation from Raoult's Law. How to predict that whether a solution of two given ...
10
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4
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Can a solvent be a solid?
Can a solvent be a solid? I do not think so. But is it possible for a solvent to be a solid?
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1
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Determining solvent and solute [closed]
On which conditions does determining solvent depend on?
1. the higher boiling indicates the solvent
the material with the higher concentration is the solvent
the solvent is kept first in a pot. ...
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2
votes
1
answer
689
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Creating a 10 ppb Lead Nitrate Solution
I’m trying to make a 10 ppb Lead Nitrate solution as part of a concentration calibration step for a Beer Lambert’s Law experiment. I plan on performing a dilution in three steps. The calculations have ...
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1
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80
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thinking about osmotic pressure when liquid is replaced by gas
An option in my test says:
"The osmotic pressure of a dilute solution is the same as it would exert if it exists as a gas in the same volume of the solution and at same temperature."
I'm not able ...
0
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1
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284
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Cross checking the fact that gas solubility decreases with temperature increase and Henry's law's validity
It is known that the solubility of gas decreases with increase in temperature which is due to the kinetic energy freeing the solute particles into the vapor phase. Henry's law states that the partial ...
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1
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Where do the electrons in lead–acid battery come from? [closed]
$$
\begin{align}
\ce{PbO2 + H2SO4 &-> PbSO4 + H2O + O} &\quad &\text{(anode)}\\
\ce{Pb + H2SO4 &-> PbSO4 + H2} &\quad &\text{(cathode)}
\end{align}
$$
The cathode’s $\ce{...
4
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0
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457
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Is there an adhesive that is not dissolved by acetone?
I am trying to glue glass sheets together to make a sealed 13" x 13" x 13" box. Inside this box there would be acetone gas used to melt 3D printed parts to make them more durable. Acetone will remove ...
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2
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Calculating ratio of conjugate base and acid when pH and pKa are given
Buffer solutions are used by biological mammalian systems to maintain the $\mathrm{pH}$ of blood plasma within a narrow range. In these systems, the compound from which this solution is obtained is $\...
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1
answer
640
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Why do azeotropes boil at constant temperature? [closed]
As given in the Wikipedia page,
An azeotrope (/əˈziːəˌtroʊp/) or a constant boiling point mixture is a mixture of two or more liquids whose proportions cannot be altered or changed by simple ...
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2
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691
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In a double displacement reaction, why don’t the two products reform after being dissolved in water? [duplicate]
Let’s say I have $\ce{AB (aq) + CD (aq) —> AD + CB}$. When AB and CD are dissolved in water, they get dissociated into their component ions. But why don’t they reform as AB and CD, if it is already ...
3
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2
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175
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What is the easiest way to concentrate a solution without causing it to hydrolyze?
I’ve been working with iron acetate solutions in dilute acetic acid (vinegar) and I’ve been running into a problem. Every time I try to boil off the solvent the solution hydrolyzes to form iron oxides....
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votes
1
answer
95
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Difference between homogeneous and heterogeneous mixture [closed]
When i mix two equal but large number of stones it is possible (though extremely unlikely) that stone a and stone b perfectly segregate themselves into two halves or that they are uniformly ...
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1
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5k
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Confusion on when to use mass of entire solution when performing q=mc∆T
I hope you are having a good day.
I am studying for the AP Chemistry exam in May 2020. While studying, I encountered a doubt.
In Problem 1 (the question on the top), the educator saw that the ...
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votes
1
answer
44
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Solutions and Precipitates [closed]
If a solution of $\pu{20mL}$ of $\pu{ 0.050M}~\ce{K+ }$is added to $\pu{80mL}$ of
$\pu{0.50M}\ce{ClO4-}$ will a precipitate form and what is the value of $Q_\mathrm{sp}$? For $\ce{KClO4}, K_\mathrm{...
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