Questions tagged [precipitation]
For questions related to the chemical reactions and processes that result in a chemical reaching its solid phase.
120
questions
18
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3answers
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How do Precipitation Reactions behave in the Absence of Gravity?
How do precipitation reactions behave in the absence of gravity, say on the International Space Station (ISS)? I have seen water taking the shape of a sphere and not that of the container in space due ...
-3
votes
1answer
47 views
Finding the percentage of chloride in an unknown solution [closed]
“A student dissolves 0.907g of an unknown solid in water. He adds excess AgNO3 and precipitates AgCl. He obtains 2.350g of AgCl. What is the percent of Chloride in the unknown solid?”
Hello I’m ...
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0answers
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How can I calculate molar concentration from a precipitate? [closed]
In a sample of water, $V=\pu{1000 mL}$, I found the concentrations of $\ce{Mg^2+}$ and $\ce{Ca^2+}$ ions that cause the hardness of the water. Then added enough $\ce{Na2CO3}$ to get $\ce{MgCO3}$ and $\...
0
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0answers
21 views
Can classification techniques used for identifying solids be used to identify precipitates?
I am preparing for an assessed practical experiment where an unknown precipitate must be identified. I know that precipitates are insoluble, and my textbook says they are considered to be solid with ...
-1
votes
1answer
23 views
Using a weak acid to prevent the precipitation of Mg(OH)2
I have this exercise in my chemistry book, and I have been staring at it for so long but unfortunately I have no single idea what to do and where to start. I will be so thankful for any help.
$0.05$ ...
4
votes
1answer
91 views
Why is only the carbonate anion used to precipitate Barium?
Q: Why is the $\ce{CO3^2-}$ anion used to precipitate Barium from $\ce{BaBr2}$ and not another anion, such as $\ce{PO4^3-}$, or $\ce{SO4^2-}$?
I am studying high school Chemistry, and the current ...
0
votes
1answer
132 views
Which metal ions precipitate in NH4OH? [closed]
From Wikipedia-1, and from an answer here on Stack-Exchange, I can list at least the following elements which will dissolve in aqueous $\ce{NH4OH}$:
$\ce{Cr(III), Co(III), Ni(II), Cu(I, II), Zn(II), ...
1
vote
2answers
75 views
Which salts can be used to precipitate chloride ions? [closed]
We don’t have AgNO3 in the lab. I have no idea what else can be useful.
I am washing a product and I want to make sure the chlorides are washed away.
1
vote
1answer
35 views
Can I safely use a separatory funnel to extract the precipitate from a solution?
Can a separatory funnel be used to collect a precipitate, or would that risk clogging the stopcock on it?
I'd like to recoup the precipitate for filtering without passing the entire solution through ...
0
votes
0answers
40 views
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 ...
2
votes
1answer
130 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. ...
4
votes
3answers
266 views
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{...
2
votes
0answers
23 views
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 ...
0
votes
1answer
53 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. ...
1
vote
1answer
607 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?
1
vote
1answer
68 views
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 ...
0
votes
2answers
24 views
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. ...
0
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0answers
195 views
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 ...
1
vote
1answer
56 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:
$$\ce{Hg^2+ + 2 I- ⟶ \underset{insoluble red ...
1
vote
0answers
35 views
how can I predict the rate of water ions precipitation on a surface?
Consider a titanium pot that contains 1kg water with the following ions:
$[Ca^{2+}]=22000$ ppm, $[Mg^{2+}]=1500$ ppm,$[Sr^{2+}]=791$ ppm,$[Na^{1+}]=48000$ ppm,$[Cl^{1-}]=120000$ ppm,$[SO_4^{2-}]=...
1
vote
2answers
61 views
Precipitation of AgCl from the tap water solution of the group 2 chloride
I had this question about an experiment where the group 2 chloride was dissolved in distilled water and excess $\ce{AgNO3}$ was added to the solution to form $\ce{AgCl}$ precipitate. One of the sub-...
0
votes
1answer
79 views
Is the water in an aqueous solution undergoing a reaction considered part of the system or surroundings?
System: In chemistry, a system is a chemical reaction. A system operates within its surroundings. Energy can move between the two.
Surroundings: The environment around a particular chemical reaction....
1
vote
4answers
297 views
How to get a precise answer to a textbook precipitation problem?
This question concerns a textbook problem* on precipitation. Briefly, there are $2\cdot10^{-4}$ of Mn$^{2+}$ and Cu$^{2+}$ ions in a liter of solution with $0.003$ M HClO$_4$. This solution is then ...
-1
votes
1answer
42 views
How to distinguish between iron and nickel based on the mass of precipitate formed with sodium hydroxide?
For the reactions shown below, we added $\pu{5.00 mL}$ of $\pu{0.0390 M}$ $\ce{NaOH}$ to a test tube containing one of the two cations $\ce{Ni^2+}$ or $\ce{Fe^3+}$ and recovered $\pu{0.00695 g}$ of ...
1
vote
1answer
693 views
Precipitation titration with Volhard method
In the Vollhard method Chloride is precipitated from a solution using escess silver ions.
$$\ce{Ag+_{(aq)} + Cl-_{(aq)} -> AgCl_{(s)}}$$
After precipitation the solution is filtered and ammonium ...
4
votes
1answer
289 views
Mathematical explanation of blank titration in Mohr method for argentometry
In my book it is written that in order to minimize systematic error in Mohr method for argentometry it is a common procedure to conduct a blank titration with $ \mathrm{Ag^+} $ against a $\mathrm{CrO_{...
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votes
1answer
1k views
Why do aluminum, magnesium, and calcium form white precipitate when mix with sodium hydroxide?
Why do aluminum, magnesium, and calcium form white precipitate when mix with sodium hydroxide? Shouldn't there be no reaction? Because sodium is more reactive than all of those element, it should be ...
1
vote
1answer
299 views
Precipitation of CaCl2 and FeCl3 in Na2CO3 [closed]
Why does $\ce{CaCl2}$ gives precipitation of $\ce{CaCO3}$ when $\ce{Na2CO3}$ is added, but $\ce{FeCl3}$ does not give the precipitation of $\ce{Fe2(CO3)3}$ in $\ce{Na_2CO_3}$ ?
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votes
1answer
158 views
Amonium perchlorate [closed]
I want to make amonium perchlorate, having amonium chlorate. If I have a solution of sodium chlorate and I add amonium chlorate, will precipitate into amonium perchlorate? Or it is with a solution of ...
0
votes
1answer
40 views
Volume of NaOH needed to precipitate copper(II) but not calcium
I have $\ce{NaOH}: C = \pu{0.1M}, V_{\ce{NaOH}}$ that I want to progressively add in a solution (in water) of:
$$\begin{align}
\ce{Cu^{2+}}&: \pu{0.01M}; & K_\mathrm{sp} &= 10^{-18.6} \\
\...
0
votes
1answer
95 views
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 ...
0
votes
1answer
424 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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votes
1answer
107 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^...
7
votes
3answers
1k 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 $\ce{Ca(OH)2}$ $(K_\mathrm{sp} = \pu{8.0 \times 10^-6})$, ...
11
votes
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 ...
3
votes
1answer
65 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
51 views
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 $\ce{Mg(NO3)2}$ ...
4
votes
1answer
331 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. (...
0
votes
1answer
1k 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 ...
0
votes
1answer
86 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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votes
1answer
83 views
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{...
10
votes
1answer
374 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 ...
5
votes
3answers
9k views
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 ...
0
votes
3answers
85 views
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 ...
4
votes
2answers
225 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 ...
5
votes
1answer
551 views
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 ...
0
votes
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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votes
1answer
12k 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 ($\ce{Na2CO3}$)....
0
votes
1answer
512 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 ...
0
votes
1answer
347 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 ...
