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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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26
votes
1answer
575 views

Why is it that every snowflake is unique?

It's pretty hard to believe in around 4.5 billion years of this planet's existence, no snowflake pattern was repeated, and that's not including potential earth-like planets. Is there a proof to the ...
11
votes
3answers
2k views

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 ...
11
votes
1answer
174 views

In the wet medium of an ocean, how does a hard shell form?

In general, if you were to try make something hard in a liquid medium (especially water) it is quite difficult to make the material solid. Things such as mollusks though, have no problem generating ...
10
votes
3answers
2k views

Experimental calculation of solubility product constant

In order to calculate the $K_\mathrm{sp}$ of lead(II) iodide, I mixed $\pu{6.0 mL}$ of $\pu{0.01 M}$ $\ce{Pb(NO3)2}$, $\pu{6.0 mL}$ of $\pu{0.02 M}$ $\ce{KI}$, and $\pu{8.0 mL}$ of water, and a ...
10
votes
1answer
372 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 ...
8
votes
5answers
14k views

What is the simplest way to create a precipitation reaction at home

Whats the easiest way to create a precipitation reaction at home? (Preferably with easily retrievable chemicals) I need this because I'm making a video for my film education.
8
votes
4answers
108k views

Reaction of silver nitrate and hydrochloric acid

Consider the reaction of $\ce{AgNO3}$ and $\ce{HCl}$. I read that silver chloride would be formed. But $\ce{H} > \ce{Ag}$ in reactivity, then how could $\ce{Ag}$ displace $\ce{H}$ from $\ce{HCl}$ ? ...
8
votes
2answers
2k views

Why do carbonates, oxides, and pure metals precipitate before metal sulfides?

Water tends to leach metals near the surface and deposit them deeper through precipitation in two layers. The upper layer is usually made of metal carbonates, oxides, and occasionally pure or native ...
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 $\ce{Ca(OH)2}$ $(K_\mathrm{sp} = \pu{8.0 \times 10^-6})$, ...
7
votes
3answers
14k views

Why does silver sulfate not precipitate in this double displacement reaction?

Aqueous silver nitrate is mixed with aqueous sodium sulfate. We were asked to perform this reaction in lab in my chemistry class, and we did not observe a precipitant being formed. However, the ...
6
votes
3answers
8k views

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?
6
votes
2answers
9k views

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 ...
6
votes
1answer
464 views

What chemical reaction can cause this blue-ish deposit?

Recently I noticed that some of our glasses and cutlery had developed a blue-ish deposit as you can see for the two sets of spoons below. For each set the spoon on the left has the blue-ish deposit ...
6
votes
1answer
2k views

Saturation of multiple solutes

Can a liquid which is saturated with a single solute, dissolve a different solute, or is saturation a universal thing? I ask because I’ve seen that different solutes have different points (amounts) at ...
6
votes
2answers
569 views

How to find the mass of dissolved AgCl when placed in a solution of NaCl?

I think the following problem in my textbook is malformed: Solid $\ce{AgCl}$ is placed in $1\,\mathrm{L}$ of $0.55\,\mathrm{M}$ $\ce{NaCl}$. Find the mass of $\ce{AgCl}$ which dissolves. I know ...
6
votes
1answer
615 views

How can I make a black precipitate without a sulfide?

I'm supposed to make a black precipitate using only the following chemicals: copper sulfate(II), lead nitrate, acetic acid, barium chloride, sodium hydroxide, copper(II) carbonate, methanol, potassium ...
6
votes
1answer
122 views

Determine the concentration of hydrogen cations to prevent precipitation of monocalcium phosphate?

Determine the $\ce{[H+]}$ needed to just prevent precipitation by $\ce{H2PO4-}$ in a $\pu{0.25 M}$ $\ce{H3PO4}$ solution that has $\ce{[Ca^2+]} = \pu{0.15 M}$. The $K_\mathrm{a1}$ of $\ce{H3PO4}$ is ...
5
votes
1answer
1k views

Constructing an equation for the precipitation of a salt

I was asked to write a balanced equation, as well as the net ionic equation, for the formation of $\ce{CaCO3}$ by precipitation. The equations should also include state symbols. Unfortunately, I am ...
5
votes
1answer
8k views

What is the chemical composition of Turnbull's blue?

I was studying qualitative analysis from this book and I found some tests for testing the presence of the cation $\ce{Fe^{++}}$. There was a test in which we add $\ce{K4[Fe(CN)6]}$ solution to a ...
5
votes
1answer
548 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 ...
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 ...
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 ...
4
votes
3answers
250 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{...
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 ...
4
votes
1answer
270 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_{...
4
votes
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 ...
4
votes
2answers
349 views

What's the reddish powder that oozes out of a black rock?

As an artist, some of the work I do involves the use of seashells, sea rocks/stones, etc. I picked up a black rock from shore at one of the beaches here in Florida and it looked somewhat clumpy with ...
4
votes
1answer
330 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. (...
4
votes
1answer
2k views

How to determine which salt will precipitate from a solution containing multiple ions?

I have a solution containing $0.2\:\mathrm{mol}$ of $\ce{Br^-}$ ions and $\ce{SO_4^2-}$ ions each. Now if I add excess $\ce{AgNO3}$ in this solution, what will precipitate? $\ce{Ag2SO4}$ or $\ce{...
4
votes
1answer
510 views

Gravimetric analysis of barium or sulfate

Which is a better way to obtain barium sulfate precipitate for gravimetric analysis: by adding $\ce{Ba^2+}$ ions to sulfate ion solution, or the other way round? I think it is better to precipitate ...
4
votes
1answer
94 views

Measurement of Water Clarity

Turbidity is essentially the clarity of water. Turbidity can be measured in many ways such as a turbidimeter, secci disk or a turbidity tube (which incorporates a secci disk at the bottom). If you had ...
3
votes
4answers
21k views

Difference between precipitation and crystallisation

What is the main difference between precipitation and crystallization. Is precipitation a chemical change and crystallization a physical change. How can we say that the resulting solute is precipitate ...
3
votes
3answers
800 views

Obtain precipitated iron?

Is it possible to obtain pure, precipitated iron with no oxidation by some chemical process? Alternatively is it possible to electrically purify iron using an anode and cathode?
3
votes
2answers
2k views

Method and Tips for Inorganic Qualitative Analysis

In a few weeks time, I will be doing an inorganic qualitative analysis test which is very pressed for time (a majority of people don't finish). The form of the test is most likely going to be that ...
3
votes
2answers
5k views

Why are transition metal hydroxides insoluble?

From what I understand, adding $\ce{NaOH}$ to a solution containing transition metal ions gives transition metal hydroxide precipitates. Why is $\ce{NaOH}$ soluble but transition metal hydroxides ...
3
votes
2answers
3k views

Why did my iron nails not dissolve in hydrochloric acid?

I was trying to dissolve iron metal in HCl to make iron chloride, but ran into some problems. I'll give a brief background of my experiment. I took iron nails and put them in a container filled with ...
3
votes
1answer
5k views

Do all double displacement reactions have precipitates?

I know that most of the double displacement reactions form some kind of precipitates in their products. But do all of the double displacement reactions form precipitates? I have searched on this site ...
3
votes
1answer
1k 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 ...
3
votes
1answer
61 views

Chemical based Water Purifier

I am currently researching as too which is better for purifying a water sample. I have obviously tried the standard Google search for 'Aluminium Sulphate or Ferric Chloride' and have come up with lots ...
3
votes
1answer
176 views

Alkalinity in Water

If you add Alum - $\ce{Al2(SO4)3}$, to a clay water sample which contains $\ce{Ca(HCO3)2}$ - due to the water's alkalinity, the pH of this water sample would drop as Alum drops the pH levels. How ...
3
votes
1answer
54 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 ...
3
votes
0answers
221 views

The behaviour of Ag3PO4 in solution

To a $\pu{1L}$ flask, we add $\pu{4.1900 g}$ ($\pu{0.01001 mol}$) of $\ce{Ag3PO4}$, then fill it up with water. Knowing the following constants, we are asked to find the concentration of all species ...
3
votes
0answers
150 views

How to prevent Tin ions from precipitating as Tin(II,IV) Hydroxides

Alright, so Tin ions in most of it's salts have the propensity to form Tin(II,IV) Hydroxides and then precipitating out of aqueous solutions. What can I throw in the solutions to prevent this? Using ...
3
votes
0answers
118 views

How much of the anion species is left over after the first precipitation?

Some barium chloride is added to a solution that contains both $\ce{K2SO4}$ ($\pu{0.050 M}$) and $\ce{Na3PO4}$ ($\pu{0.020 M}$). (a) Which begins to precipitate first: the barium sulfate or the ...
2
votes
2answers
15k views

Reaction of citric acid and calcium chloride

I was planning to extract citric acid from lemon juice by reacting the lemon juice with calcium chloride hoping it would react to form calcium citrate and precipitate according to the reaction $$\ce{...
2
votes
2answers
861 views

What is the precipitate of this reaction of magnesium?

$\ce{MgSO4}$, on reaction with $\ce{NH4OH}$ and $\ce{Na2HPO4}$, forms a white crystalline precipitate. Identify the precipitate. My approach: I guess the white crystalline precipitate is $\ce{Mg(OH)2}...
2
votes
2answers
194 views

Is there an alternative wet chemical method or electrochemical method to obtain precipitation of iron, nickel and silicon powder? [closed]

There are many methods available to obtain powdered metals and alloys. Wikipedia show some of them. Another form is grinding with posterior removal of wheel particles. All these methods produce metal ...
2
votes
1answer
2k views

Is an iron (II) sulphate solution supposed to turn cloudy when silver nitrate is added?

$\ce{AgNO3}$ is not suppose to cause a precipitation when mixed with $\ce{FeSO4}$, but the acidified solution turns slightly cloudy when $\ce{AgNO3}$ is added. Is this suppose to happen? solutions ...
2
votes
1answer
92 views

Precipitaiton of aragonite

I'm not positive what this questions is asking. The prompt says "Write balanced equations for the following processes. Chemical species should be the dominant ones at the given $\mathrm{pH}$. Show ...
2
votes
1answer
346 views

Analysis of mixture by precipitation and complexometric titrations

I've performed an experiment about chloride mixtures. First using $\ce{AgNO3}$ as titrant, I've titrated the mixture to determine the amount of total chloride. Then by direct titration with $\ce{EDTA}$...