Questions tagged [water]

For questions relating to water (H₂O), specifically its structure, properties, and uses in chemistry. For questions not about water but rather about solutions in water, use tags [aqueous-solution] or [solubility] instead.

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25
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4answers
19k views

Hypothetical: What happens to water as pressure increases to infinity? [duplicate]

I've asked a similar question here but the answer given shows the behaviour of water under general conditions. I'd like to know what the behaviour of water is like as pressures increase towards ...
28
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2answers
14k views

Is methanol more acidic than water?

Methanol is slightly more acidic than water. Their $\mathrm{p}K_\mathrm{a}$ values, in water, are $15.5$ and $15.7$, respectively. All other aliphatic alcohols, however, are less acidic than water. ...
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2answers
14k views

Why is water not part of the equilibrium constant?

In the acid base reaction $$\ce{NH4+ + H2O <-> NH3 + H3O+}$$ the acidity constant, which is a relation between concentrations is given by $$K_{\mathrm{a}}=\frac {\ce{[NH3]} \cdot \ce{[H3O+]}}{...
28
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2answers
5k views

What happens if you cool water in a container too small for it to freeze?

Freezing a full bottle of water tends to shatter the glass bottle. What if you used something tougher than glass, like diamond? What would happen if you kept dropping the temperature, but restrained ...
16
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5answers
33k views

Is pure water very corrosive?

In other site, someone claimed that pure water is very corrosive. Water distilled for some laboratory uses (like the Z-pinch reactor) is distilled to 0.00000009% purity, and is caustic enough to ...
28
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2answers
2k views

Why is snow white?

I know that this is a rather ambiguous question; but my question is, whenever we take water and freeze it in the freezer, it still tends to stay clear. Since snow is just frozen water, why is it white?...
39
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2answers
3k views

Are the lone pairs in water equivalent?

I've read that the oxygen atom in water is $\mathrm{sp^2}$ hybridized, such that one of the oxygen lone pairs should be in an $\mathrm{sp^2}$ orbital and the other should be in a pure p atomic orbital....
17
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2answers
11k views

Does water have a chemical name?

The title sums up the question: Does water have a chemical name? If so, what is it? P.S. I checked up the web and got all sorts of crazy answers like dihydrogenmonoxide, oxidane, ...
24
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2answers
27k views

Why is water a dipole?

Water ($\ce{H2O}$) is a dipole. The reason why is simply because it is not symmetrical, there are more electrons on the oxygen side than on the hydrogen side, and the electronegativity of oxygen. But ...
17
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4answers
17k views

Why is H₂O V shaped? [duplicate]

We know that the molecule of H₂O is V-shaped. This is what makes it a dipole. But why is that? I mean, if the hydrogens have a partial positive charge, then they should try to get away from each ...
16
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4answers
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How to RAISE the melting point of water?

It is common that adding common salt into water will lower its melting point. But, is there any way to RAISE the melting point of water? Does it lower the boiling point of water as well? Why?
12
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1answer
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What happens to water under high pressures without possibility of escape?

Knowing very little about the nature of water, wondering how it might behave at the centre of a planet or centre of an another massive gravitational body. Could water take such pressures or might it ...
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1answer
2k views

Is methanol really more acidic than water?

The question Why is methanol more acidic than water? deals with the reasoning of why methanol is more acidic than water. However, as mentioned in the comments of that question, the acidity constant of ...
2
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2answers
1k views

How concentrated can an acid be?

How concentrated can an acid be without it being supersaturated? Is there a certain limit to how concentrated an acid or base can be? When I mean concentration, I mean molarity; so how concentrated ...
-2
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1answer
162 views

Frequency of Mpemba Effect

What are the chances of warm water freezing faster than cold water? (How many percent?) Does it have to do with container size or something in it?
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0answers
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Does water really have strong EM absorption at 3 kHz in solid and 2 GHz in liquid? Why the huge shift?

While writing this answer to the question Transmitter receiver coil separation for Electromagnetic Terrain Conductivity Measurement I ran across this large PDF file of a book Soil and Environmental ...
19
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2answers
44k views

Why does water evaporate at room temperature?

When water temperature reaches $100\ ^\circ \mathrm{C}$, the molecules get so excited that the hydrogen atoms lose the bonds to the oxygen atom and therefore the water starts to become gas. I get that,...
16
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3answers
9k views

Is there a simple way to separate deuterium oxide from tap water?

I understand that tap water contains minute amounts of deuterium oxide (heavy water). Is there a simple way to separate, concentrate the $\ce{D2O}$?
13
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2answers
6k views

Burns from boiling water and steam

Why is a burn to the skin caused by steam more serious than a burn caused by the same amount of boiling water at the same temperature? The temperature is the same, which implies that the kinetic ...
17
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7answers
43k views

Why can't pure water conduct electricity since it can be reduced at cathode and oxidised at anode?

We all know that pure water can't conduct electricity. But during electrolysis, if add a small amount of $\ce{HCl}$ acid inside, water could be decomposed to hydrogen gas and oxygen gas, as it is ...
6
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2answers
1k views

Estimation of the bond angle of water

We know from experimental data that $\ce{H-O-H}$ bond angle in water is approximately 104.5 degrees. If its two lone pairs were bonds (which is unfortunately impossible) also $\ce{O-H}$ bonds and a ...
5
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3answers
644 views

In my homemade electrolysis setup, only the negative end bubbles?

I've created an electrolysis setup by connecting a $6~\mathrm{V}$ battery to a cup filled with saline water via pencils; I am confused as to why only the negative pencil bubbles though. After running ...
3
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1answer
3k views

Does NaCl reduce the surface tension of water?

Does NaCl reduce the surface tension of water? And why? For example soap does it, and I was wondering if NaCl does the same.
2
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1answer
616 views

Chalcogens' hydrides as acids?

I've noticed that chalcogens never form binary acids, and instead end up like water, with very little acidity. Why is this? Or am I wrong and there's a counterexample, if so please give it.
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2answers
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What is the cause of hygroscopy?

Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment. Why are some compounds hygroscopic and others are not? What is it about their ...
14
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3answers
9k views

Do chemists refer to water as “dihydrogen monoxide”?

Is the name "Dihydrogen monoxide" actually what chemists would use to refer to $\ce{H2O}$ (assuming there was no common name, "water")? Of course, this is all over the internet. I'm a little ...
12
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3answers
35k views

Why isn't water an ionic compound?

If two alkali metal atoms join with an oxygen atom, an ionic bond forms. Since hydrogen has the same number of valence electrons as alkali metals, why can't water be ionic? This is what I'm thinking:...
11
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3answers
8k views

Can you heat water with additives?

I have been curious about this question for a while. If you want to warm up a large amount of water, is it feasible to do this by adding a substance that has an exothermic reaction with the water? ...
2
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1answer
157 views

When it rains, it puddles. Spilled salt cycles between wet and dry with humidity. Is this akin to a phase change?

I have some spilled un-iodized table salt (NaCl). It is very humid where I live, and when it gets very humid for a few days, the salt absorbs so much water that it becomes a puddle of (probably) ...
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1answer
655 views

How many hydrogen bonds are formed by water and by HF?

How many hydrogen bonds are possible for $\ce{H2O}$, given that oxygen has two lone pairs? Is it 4 or 2? Related: why is it that HF forms only 1 hydrogen bond, given that HF has three lone pairs?
129
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7answers
36k views

Why doesn't water burn?

Hydrogen is flammable, and for any fire to burn it needs oxygen. Why does a compound made of hydrogen and oxygen put out fires instead of catalyzing them? I understand that hydrogen and water are ...
41
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9answers
422k views

Why does ice water get colder when salt is added?

It is well known that when you add salt to ice, the ice not only melts but will actually get colder. From chemistry books, I've learned that salt will lower the freezing point of water. But I’m a ...
28
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5answers
13k views

Why is water “the universal” solvent?

This is an old question that our textbook tried to answer but worsened the situation. Many things are soluble in water. So many, that studying solutions will always require studying aqueous ones. It ...
21
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1answer
1k views

Are there any known chemical properties of tritium water that make it unusually different from protium water?

I suppose the first question supporting the main question is, has tritium water ever been synthesized in sufficient quantity to test chemical properties? If so, and apart from the obvious radioactive ...
19
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5answers
51k views

Why does hydrogen fluoride have a boiling point so much lower than that of water?

$\ce{F}$ has more unshared electron pairs and is very electronegative, so $\ce{H}$ of another $\ce{HF}$ molecule can $\ce{H}$-bond with it. $\ce{HF}$ has normal boiling point of $\pu{19.5^oC}$ while $...
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2answers
10k views

Why does water volume decrease when salt is added?

Why does water volume decrease when salt is added? Our teacher asks us in the class but I don't find any strong reason.
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2answers
2k views

What is a product of water ionization?

I've read that radioactive compounds are dangerous because they emit electromagnetic waves (gamma-radiation etc.) that are dangerous for living organisms because they can ionize atoms in molecules. ...
3
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2answers
1k views

Can water be liquefied or solidified just by adjusting the temperature, regardless of the pressure?

technically the line between liquid and solid phase would go a long way before hitting the y-axis, but the point is it will eventually. So the question remains, can any liquids, including water (with ...
2
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4answers
5k views

Sensitive test for lead in water?

Some of my friends are in Flint and I'm horrified by their situation. I would like to learn how to test for lead independently. After all if you can't trust the state sending them water to test is ...
12
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3answers
4k views

Why doesn't a table sublimate, while ice does?

A table does not sublimate, and nor does a spoon. Ice does, however. What is the fundamental difference?
11
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4answers
291 views

Is there any electronic component to water conductivity?

Answers to Decrease in temperature of a aqueous salt solution decreases conductivity indicate that the electrical conductivity of salt solutions arises from the mobility of ionic species and therefore ...
7
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1answer
1k views

Vaporized sodium hydroxide?

Some time ago, I was making a $\ce{NaOH}$ solution. The solution I had made was much too concentrated, and the heat released in the dissolution of the ions caused the water to begin steaming. ...
5
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1answer
2k views

How much ascorbate to neutralize one liter of chlorinated tap water?

In Las Palmas de Gran Canaria, tap water is chlorinated. In an Internet forum, someone claims that in 2008 the water had a chlorine concentration of 0,5 - 1mg/l. On the official site of Emalsa, the ...
4
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1answer
4k views

Are there any other elements that get less dense in their solid state?

I was learning about how water, because of its hydrogen bonds, actually gets less dense as it goes into its solid state - I was just wondering, what other elements do this? Are they similar to water? ...
2
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2answers
10k views

How does a water molecule bond to an anhydrous salt to form a hydrate?

Some sites suggest that water molecules bong to anhydrous salt via a "loose bond". What does that even mean? $\ce{H2O}$ is a polar molecule and salts are made up of ionic bonds. Is it a hydrogen bond ...
0
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1answer
143 views

What is a hydrogen bond?

I was doing a little research on the Chemistry of water, and it said that water molecules have a hydrogen bond between them. What is it, and what does it do to water?
12
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3answers
29k views

How is dissolving a physical change and not a chemical change?

When salt dissolves in water it dissociates and it is no longer in a lattice structure. The electrostatic forces are no longer there and are replaced by water-ion interactions. To me that sounds like ...
10
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2answers
4k views

How can I identify whether a substance is KOH or NaOH?

I've bought $\ce{NaOH}$ or $\ce{KOH}$ (I don't remember which one!) for my electrolyzer and I've tested it. Now I want to improve its performance and I was searching for a better electrolyte when I ...
10
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4answers
5k views

Chemical properties of isotopes

I've always heard that different isotopes of the same element have exactly the same chemical properties. But for example, I've read that some compounds which have hydrogen atoms interchanged by ...
5
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1answer
185 views

Is there an electrolyte that will halt the production of Hydrogen in water electrolysis?

Care must be taken in choosing an electrolyte, since an anion from the electrolyte is in competition with the hydroxide ions to give up an electron. An electrolyte anion with less standard electrode ...