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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Why does Mg(HCO₃)₂ on heating gives Mg(OH)₂? [duplicate]
Normally, bicarbonates on heating forms carbonates.
Why does Mg not give this too?
In a reference book I am referring to, it is given that it is due to high solubility product of Mg(OH)₂ compared to ...
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1answer
61 views
How to find the concentration of barium ions in a mixture of barium sulfate and barium thiosulfate?
I have a hard time with selective precipitation problem.
A mixture of $\ce{BaSO4}$ and $\ce{BaS2O3}$ is shaken with pure water until a saturated solution is formed. Both solids remain in excess. ...
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3answers
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CaSO4 precipitate in mixture of Na2SO4 and CaCl2 solutions
I have been stuck on a chemistry problem for a long time now and if anyone here can help me I would be eternally grateful.
40. Du tillsätter $\pu{100 ml}$ $\pu{0,01 M}$ $\ce{Na2SO4}$-lösning i $\pu{...
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Why does lead chloride not precipitate from a lead chlorate solution with KCl?
$$\ce{Pb(ClO_4)_2(aq) +2KCl(aq) -> PbCl_2(s) + 2KClO_4}$$
A chemist mixes a dilute solution of lead perchlorate with a dilute solution of potassium chloride to precipitate lead(II) chloride ($K_\...
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Cleaning a stubborn Electrospray residue
I have an electrospray ionization capillary tip that sprays into a chamber that contains some circuit boards. An aqueous CsI sample is apparently causing a white residue to build up on these boards ...
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1answer
24 views
Precipitation of Cu2+ and Pb2+ ions
Hi chemistry enthusiasts!
I am working on my scholarship exam practice. I believe this exam assumes high school + first year university knowledge although the standard may be varied across the world. ...
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1answer
83 views
Are precipitations exothermic and/or endothermic?
Should be an easy one. I'm fumbling a concept. I've read precipitations are exothermic. Is this accurate? Why would there be no endothermic precipitation reactions?
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1answer
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Making hard water
Does anyone know how to make hard water with a hardness of 200+ ppm in terms of $\ce{CaCO3}$?
I live in Seattle and we have very soft water and we need hard water for testing purposes. Obviously you ...
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2answers
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Influence of pH on precipitate crystallite sizes?
It's normally assumed that a higher pH of solution would slow nucleation rates and hence lead to larger crystal formation. I've found literature that it is due to solid-liquid inter-facial tension. ...
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0answers
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Eutectic Phase Diagram of Al-Si Analysis
Hello,
How can I know from this phase diagram:
1. The composition of the alloy Al-Si that allows precipitation to occure?
2. The range of temperatures where the Al-Si is soluble?
3. The range of ...
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1answer
49 views
How to convert soluble colorless [HgI₄]²⁻ back to insoluble red HgI₂? [closed]
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
57 views
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
42 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....
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4answers
281 views
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
37 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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1answer
455 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)}}$$
After precipitation the solution is filtered and ammonium ...
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1answer
205 views
Mathematical explanation of blank titration in Mohr method for argentometry
In my book it is written that in order to minimize systematic error in Mohr method for argentometry it is a common procedure to conduct a blank titration with $ \mathrm{Ag^+} $ against a $\mathrm{CrO_{...
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1answer
891 views
Why do aluminum, magnesium, and calcium form white precipitate when mix with sodium hydroxide?
Why do aluminum, magnesium, and calcium form white precipitate when mix with sodium hydroxide? Shouldn't there be no reaction? Because sodium is more reactive than all of those element, it should be ...
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1answer
250 views
Precipitation of CaCl2 and FeCl3 in Na2CO3 [closed]
Why does $\ce{CaCl2}$ gives precipitation of $\ce{CaCO3}$ when $\ce{Na2CO3}$ is added, but $\ce{FeCl3}$ does not give the precipitation of $\ce{Fe2(CO3)3}$ in $\ce{Na_2CO_3}$ ?
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Amonium perchlorate [closed]
I want to make amonium perchlorate, having amonium chlorate. If I have a solution of sodium chlorate and I add amonium chlorate, will precipitate into amonium perchlorate? Or it is with a solution of ...
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1answer
38 views
Volume of NaOH needed to precipitate copper(II) but not calcium
I have $\ce{NaOH}: C = \pu{0.1M}, V_{\ce{NaOH}}$ that I want to progressively add in a solution (in water) of:
$$\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
364 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
102 views
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
950 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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3answers
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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
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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
280 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
729 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
80 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
349 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
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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
2k views
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
10k 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
446 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
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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
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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
2k views
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
9k views
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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2answers
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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
972 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
34 views
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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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
924 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?
