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Questions tagged [precipitation]

For questions related to the chemical reactions and processes that result in a chemical reaching its solid phase.

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1answer
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How to convert soluble colorless [HgI₄]²⁻ back to insoluble red HgI₂? [on hold]

When a solution contains $\ce{Hg^2+}$ and $\ce{I-}$, depend on the concentration ratio of $\ce{Hg^2+}$ and $\ce{I-}$, the following reactions can happen: $$\ce{Hg^2+ + 2 I- ⟶ \underset{insoluble red ...
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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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2answers
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Precipitation of AgCl from the tap water solution of the group 2 chloride

I had this question about an experiment where the group 2 chloride was dissolved in distilled water and excess $\ce{AgNO3}$ was added to the solution to form $\ce{AgCl}$ precipitate. One of the sub-...
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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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4answers
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How to get a precise answer to a textbook precipitation problem?

This question concerns a textbook problem* on precipitation. Briefly, there are $2\cdot10^{-4}$ of Mn$^{2+}$ and Cu$^{2+}$ ions in a liter of solution with $0.003$ M HClO$_4$. This solution is then ...
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1answer
35 views

How to distinguish between iron and nickel based on the mass of precipitate formed with sodium hydroxide?

For the reactions shown below, we added $\pu{5.00 mL}$ of $\pu{0.0390 M}$ $\ce{NaOH}$ to a test tube containing one of the two cations $\ce{Ni^2+}$ or $\ce{Fe^3+}$ and recovered $\pu{0.00695 g}$ of ...
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341 views

Precipitation titration with Volhard method

In the Vollhard method Chloride is precipitated from a solution using escess silver ions. $$\ce{Ag+_{(aq)} + Cl-_{(aq)} -> AgCl_{(s)}}$$ After precipitation the solution is filtered and ammonium ...
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White deposit after adding Methanol to a beaker?

I added some methanol and boric acid to a beaker. I stirred it, and stored the solution in a glass vessel. I left the beaker out to let all the methanol evaporate, and came back a day later to see ...
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171 views

Mathematical explanation of blank titration in Mohr method for argentometry

In my book it is written that in order to minimize systematic error in Mohr method for argentometry it is a common procedure to conduct a blank titration with $ \mathrm{Ag^+} $ against a $\mathrm{CrO_{...
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648 views

Why do aluminum, magnesium, and calcium form white precipitate when mix with sodium hydroxide?

Why do aluminum, magnesium, and calcium form white precipitate when mix with sodium hydroxide? Shouldn't there be no reaction? Because sodium is more reactive than all of those element, it should be ...
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1answer
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Precipitation of CaCl2 and FeCl3 in Na2CO3 [closed]

Why does $\ce{CaCl2}$ gives precipitation of $\ce{CaCO3}$ when $\ce{Na2CO3}$ is added, but $\ce{FeCl3}$ does not give the precipitation of $\ce{Fe2(CO3)3}$ in $\ce{Na_2CO_3}$ ?
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Amonium perchlorate [closed]

I want to make amonium perchlorate, having amonium chlorate. If I have a solution of sodium chlorate and I add amonium chlorate, will precipitate into amonium perchlorate? Or it is with a solution of ...
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1answer
37 views

Volume of NaOH needed to precipitate copper(II) but not calcium

I have $\ce{NaOH}: C = \pu{0.1M}, V_{\ce{NaOH}}$ that I want to progressively add in a solution (in water) of: $$\begin{align} \ce{Cu^{2+}}&: \pu{0.01M}; & K_\mathrm{sp} &= 10^{-18.6} \\ \...
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1answer
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Is it absolutely necessary to use centrifuge to separate ethylene glycol from precipitate?

I've been trying to synthesize intermetallics of $\ce{XY}$ type using transition metal salts and main group element salts. For my system, EG, DEG, and TEG are good solvents. However, because of them ...
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1answer
306 views

Hydrolysis of transition metals' halides?

So, it's a relatively common known solubility rule that any hydroxide with a cation not in the first two groups is basically insoluble. So supposing we have a transition or post-transition metal $M$ ...
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1answer
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Determine concentration of phosphate after copper(II) oxalate is precipitated

Solution with $\ce{Na3PO4}$ with $\pu{0.02 M}$ concentration and $\ce{Na2C2O4}$ with $\pu{0.03 M}$ concentration. I add excess $\ce{Cu(NO3)2}$ very carefully – tiny amounts. What will be my $\ce{PO4^...
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3answers
707 views

How much calcium hydroxide will precipitate after addition of sodium hydroxide into saturated calcium hydroxide solution?

Below was question 34 in the USNCO 2017 exam: If $\pu{0.10 mol}$ of solid $\ce{NaOH}$ is added to $\pu{1.00 L}$ of a saturated solution of $\ce{Ca(OH)2}$ $(K_\mathrm{sp} = \pu{8.0 \times 10^-6})$, ...
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Why exactly does precipitation occur?

In a solution, we have ions floating around but when we have a precipitate, they're arranged as they would be in a solid. This conversion should cause a decrement in the entropy of the system and ...
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1answer
49 views

How dried up detergent water led to precipitation of snowflake like shapes?

I forgot to drain the water off the bucket (after cleaning stain from a piece of clothing with detergent) and left it for few days. After few days when I needed it back, I found these glittery very ...
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1answer
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Can i calculate the solution of the problem in more simple way?

and i got a serious question. During my exercises at home, i found that im struggling a lot while solving simple problem`s like this one: I have an aquatic substance with 0.100 M of $\ce{Mg(NO3)2}$ ...
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1answer
245 views

Aluminium sulphate solubility as function of the pH

earlier I asked about how to know the aluminium sulfate solubility as function of the ph (see the previous question here). I found this diagram on the page 57 of Rubin, A. J., & Hayden, P. L. (...
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1answer
594 views

Ethanol discolored yellow when stored with a rubber stopper. Forming fine white precipitate when added to water

I stored some Klean-Strip denatured alcohol in a test tube and capped it with a rubber stopper. I did this in preparation for a chemistry demonstration. When I opened my kit a few days later at the ...
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1answer
77 views

Anti-Solvent Precipitation Of Lycopene

I have a question about anti-solvent precipitation in organic chemistry: Is it possible to precipitate lycopene or other carotenes using this method? I have been extracting carotenes like lycopene ...
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1answer
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Calcium-containing acidic solution

I want to prepare an acidic solution containing Ca ions. I thought about dissolving calcium sulphate, acetate or phosphate in $\pu{2 M}$ $\ce{H2SO4}$ or $\ce{H3PO4}$ solutions, but it seems that $\ce{...
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1answer
332 views

Reaction of barium peroxide forming barium carbonate

I stumbled across this reaction: $$\ce{BaO2 + H2CO3 -> BaCO3 + H2O2}$$ This reaction seems quite similar to the variant with sulfuric acid $$\ce{BaO2 + H2SO4 -> BaSO4 + H2O2}$$ which is well ...
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2answers
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How does boiling water affect its hardness?

Does boiling water reduce its hardness, or on the contrary, increase it? It seems there are ambivalent phenomena at play here: boiling will evaporate pure water, thus increasing the concentration of ...
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3answers
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Finding ions in water samples

So for a school chemistry assignment I was given 5 water samples and a bunch of different reagents to help me find out what was in the solutions. I'm stuck on two. The first one had a pH of 7 and ...
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2answers
213 views

Finding sulfate contamination in crystallized silver nitrate

What is the best way to check for a small amount of sulfate contamination (if any) in silver nitrate? Usually, I would use dilute barium chloride to precipitate out the resulting insoluble white ...
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1answer
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Which calcium salt is good enough to make calcium benzoate?

This question is inspired from the following questions: Reaction of citric acid and calcium chloride Precipitation of citric acid by CaCl2 and Ca(OH)2? The answer to the 1st question says that ...
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1answer
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How can you make magnesium carbonate?

I am trying to start my own gym company that sells gym chalk however I have not been able to find a good process for making good magnesium carbonate. I have tried mixing equal amounts of magnesium ...
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1answer
9k views

Does sodium carbonate form a precipiate with iron (III) chloride? [closed]

Students were asked to determine a compound that could be combined with an iron (III) chloride ($\ce{FeCl3}$) solution to react and form a precipitate. A student chose sodium carbonate ($\ce{Na2CO3}$)....
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1answer
403 views

Precipitation reaction stoichiometry?

I have a question where I do not understand the final step to solve...here it is: What will be the Strontium ion concentration remaining after 30.0 mL of 0.10 M Na2SO4 solution are added to 70.0 mL ...
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1answer
207 views

How to determine the amount of barium in a sample of contaminated water?

Here is the assignment I have: You are working for Matrix Pro - a company involved in analytical assessment and method development for the clean-up of contaminated waters. You received water ...
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1answer
979 views

Turn Solution to hcl salt [closed]

I have a liquid mixture in a bottle containing different substances dissolved from their salt forms (i.e. lidocaine hydrochloride, anhydrous caffeine). These compounds are dissolved in distilled water....
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1answer
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How to remove sulfuric acid from sample

I have problem with my experiment. My experiment is acid hydrolysis of ethyl benzoate. The acid that I used is sulfuric acid. My problem is when I get the precipitate (impure benzoic acid) I have to ...
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1answer
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What is the yellow precipitate formed from reacting diamminsilver fluoride and potassium iodide?

These two compounds, silver diamine fluoride and potassium iodide (actually a solution called Lugol’s solution), are being used together in dentistry. When combined they form a yellow precipitate. I ...
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What reactions occur when mixing copper sulfate and sodium hydroxide?

I tried reacting copper sulfate with sodium hydroxide to get copper hydroxide, which should precipitate, according to the following equation: $$\ce{2NaOH + CuSO4 -> Cu(OH)2(s) + Na2SO4}$$ I ...
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1answer
928 views

Does gold always become gold chloride when dissolved with HCl and an oxidizer and can it always be precipitated with sodium metabisulfate?

I tried to extract gold from computer parts by STRIPPING the gold using $\ce{HCl}$ and $\ce{H2O2}$ by dissolving the copper & nickel underneath but i added FAR too much $\ce{H2O2}$ by a stupid ...
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1answer
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How to know when dissolution is complete?

In a given solubility equilibrium, I know that if $ Q >K_s$, then the salt will precipitate until $ Q =K_s$. If $ Q <K_s$, however, would the precipitate dissolve until $ Q =K_s$ too?
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1answer
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How to determine the minimum pH at which iron(III) hydroxide dissolves completely?

Knowing $K_\mathrm{s} = 6\cdot10^{-38}$ for $\ce{Fe(OH)3}$ in neutral solutions, calculate the minimum pH of an acidic solution in order to completely dissolve $\pu{10 mg}$ of $\ce{Fe(OH)3}$. Data: $V ...
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1answer
832 views

How to determine sulfate ions in a solution by precipitation? [closed]

For example I am given an unidentified solution and am told that it may or may not contain sulfate ions. How can I confirm or deny the presence of sulfate in this solution?
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184 views

Fast and complete ways to remove chloride from solution (sub ppb levels)

Main question: We are trying to reduce the chloride concentration in a solution to sub-ppb levels. I have to dissect a fruit fly in this solution so I am interested in removing any chloride that is ...
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2answers
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Common ion effect math problem

The question was: If you are given a $1$ Litre solution of $\ce{CaF_2}$where there is $2.0 \times 10^{-5}$ M $\ce{Ca^{2+}}$. How many mililitres of $0.1$ M $\ce{NaF}$ would you need to precipitate $...
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Triiodide ion gravimetric analysis Reaction Equation

Last week I did a gravimetric analysis from the following reaction. $\ce{AgNO3 + (CH3)4N+I3- -> AgI(s) + (CH3)4N+NO3- + I2}$ The objective was to identify if my reactant was triiodide or ...
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Do we cool the solution to form a precipitate because of lower melting points?

If we have two compounds in aqueous solution, in order to separate one from the other the solution is placed into an ice bath. For example the formation of $\ce{KClO3}$ from a combination of $\ce{...
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1answer
349 views

What is the difference between fractional freezing and fractional crystallization?

More simply put, what is the difference between freezing and precipitation when considering a mixture? Take two scenarios: First a mineral in water. If the temperature of this solution is lowered, ...
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What chemicals could be added to human urine to cause harmful chemicals to precipite out?

What chemicals could be added to human urine to render it drinkable with no harmful side effects? Urine is salty and contains other dissolved solids. Thus, drinking untreated urine would result in ...
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Growing a crystal with slow precipitation. How to do it?

Let's assume that I have two solutions and if I mix them precipitation occurs. Can I syphon the two solutions into a third container with pure solvent inside so slow, that no precipitation but ...
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3answers
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When our hard water is boiled, it leaves a blue-green residue in our kettle.

The inside of our kettle is lined in a blue-green deposit. Our water is very hard, but what minerals could cause the coloration?
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1answer
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How to calculate the amount of substance of barium sulfate that is precipitated?

Determine the amount (in mol) of barium sulfate that will be precipitated when $200.0~\mathrm{cm^3}$ of $0.450~\mathrm{mol\,dm^{–3}}$ barium nitrate solution is added to an excess of sodium sulfate ...