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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Is there a term for a gel-like substance with a higher concentration of salinity than EO water?

I am writing a story about a planet that is covered in water but the water is closer to a gel-like substance with a higher concentration of salinity than EO water. I just wanted to know if that was a ...
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inverted reverse osmosis reaction products [closed]

Is an inverted reverse osmosis leading to hydride in h2o ?
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Keto Enol tautomerism [duplicate]

I don't understand why the keto form is present more at equilibrium. Yes I know that for phenols or instances where the enol form can have H-bonding the enol form is preferred, but generally I have ...
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22 views

How can DI water inhibit peroxidase activity?

I'm troubleshooting an IHC staining issue, and according to Thermo-Fischer's website, "Deionized water can sometimes contain peroxidase inhibitors that can significantly impair enzyme activity.&...
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1answer
24 views

How does hydraulic equilibrium work on the particulate level?

I recently learned that osmosis occurs when there is a semipermeable membrane between pure water and a solution of water. The pure water then fills up the solution's side until, as my textbook put it, ...
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Would adding a water soluble salt (e.g. NaCl) affect a water sensitive reaction?

Let's take for example a reaction that would benefit from having less water in it, ester formation from alcohol and acid. We know that the equilibrium can be shifted to the right (ester formation) if ...
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leaving a spoon in a cup of tap water for about 12 hours makes a pattern of bubbles, why? [closed]

I left the spoon in the water after showing the cup from the tea that I was drinking last night makes a spoon like the pattern of bubbles
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1answer
54 views

Autoionization of water

Consider as solution of pure water at $\pu{25 ^\circ{}C}$ with a $K_{\mathrm{w}} = 10^{-14}$. If we are to add an acid to the mix we would observe an increase in hydronium and an equal decrease in ...
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Are all amphoteric substances weak acids and weak bases?

I saw as an example that water is amphoteric (to be more precise amphiprotic), and I came up with the following questions: Is there any substance that acts as a weak acid and a strong bases at the ...
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3answers
68 views

What is non toxic to fish, has a low freezing point, and floats on water?

I am looking for a liquid that floats on water that will prevent the water from freezing (or at least slow it down). The application would be a small area (less than a square foot). It has to be non-...
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Why do we omit OH- ions from H2O and acid equations [closed]

And the converse for bases why do we omit $\ce{H3O+}$ ions? Is it correct to think that when an acid is added to water it shifts the equilibrium to the right for the dissociation of water? ...
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Does a Proton Exchange Membrane let gas through? [closed]

For instance, if a PEM fuel cell is turned on it’s side, will the hydrogen and oxygen gas get through the membrane and start to mix?
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In electrolysis, why does each atom wait to turn into gas until they reach a particular electrode?

More specifically why don't bubbles of both oxygen and hydrogen appear everywhere? If the electricity just breaks apart bonds wouldn’t the hydrogen and oxygen just immediately turn into gas and bubble ...
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Enthalpy of vaporization meaning

I already know that ΔH in a vaporization is the energy needed to bring water(l) to water(g) (constant P) but... from 1st law: $$dU = dQ - dW$$ (I know I can't write dQ and dW like that but you ...
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1answer
48 views

Freezing point depression and organic molecules

Do organic molecules reduce the freezing point of water in the same way that inorganic salts do? I've recently been swimming in lakes with a high organic content (e.g. mostly tannins. There's a lake ...
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3answers
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What does heterogeneous mean?

We say that a homogeneous sample consists of the chemically same type of molecules whereas heterogeneous ones vary chemically, i.e. the molecules throughout are not same and also not uniform. Why do ...
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59 views

Dielectric constant for gases possessing van der Waals forces [closed]

I've learnt that water can dissolve ionic bonds because it possesses a high dielectric constant. In the cases of covalent compounds (especially the non-polar covalent compounds), where the molecules ...
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Is soap forming micelles in water an exothermic reaction?

I have seen it described as soap molecules releasing energy when forming micelles. Is that correct? Is it an exothermic reaction? I mean a bunch of molecules uniting to form a micelle.
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68 views

How does strong acids conduct electricity in water?

How do strong acids conduct electricity in water? I have just studied ionization of water and I'm confused about some points. First: I know that water ionizes in a very small amount ($10^{-14}$) so ...
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2answers
63 views

Why doesn't base/acid reacting with water create a salt?

An acid/base nwutralization will create a salt + water. If one uses water itself as the acid or base, and have an acid/base neutralization, how come that doesn't create a salt? For example:$$ \ce{HCN(...
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48 views

what is volume of produced gases in water electrolysis [closed]

I decided to try and determine the combined volume of O2 and H2 that could be produced through electrolysis of water. so i looked up a bunch of stats for the relevant chemicals; H O H2O g/mol 1....
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1answer
40 views

What is the 'electronic energy', in units of 'negative' hartrees, of a molecule?

On a NIST (National Institute for Standards and Technology) page on the molecular details of water and it's various isotopologues, I came across this: Electronic energy: -76.4089547246 hartree There ...
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29 views

Does water have properties suggesting it has a phase transition at 50-63 Celsius so it has two phases?

https://www.youtube.com/watch?v=YsQXN-Kh2-w&t=497s In this video, he says that water has four properties (surface tension, refractive index... ) that transition from 50 - 63 Celsius between ...
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Standard practice for keeping salts dry

I should point out first that I'm not a chemist, but I'm currently doing a little bit of chemistry; this should clarify that I don't have formal training in a chemistry lab (other than some basic chem ...
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1answer
58 views

Reaction between barium peroxide and hypochlorous acid

When $\ce{BaO2}$ reacts with $\ce{HClO},$ the question tells us that that oxygen, barium chloride and one other product is formed. The equation I came up with is $$\ce{BaO2 + 2 HClO -> BaCl2 + 2 O2 ...
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Is the average kinetic energy of evaporating water molecules (at room temperature) equivalent to the average kinetic energy of boiling water?

Purpose: On new year's eve, after a splendid red and an assortment of sumptuous repasts, I made a bold remark which, on further consideration, may turn out to be incorrect. Unless! Unless I can ...
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Columnar crystallization of ice under small pieces of eroded granite

Walking through mountains in northern Portugal I noticed a curious formation of ice cristals whose explanation I was unable to give to my grand children (Photo 1). I searched in the internet but I ...
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1answer
35 views

Do antimicrobial abilities of copper boilers decrease over time?

As copper boilers age and develop oxide buildup, does this lessen the copper's antimicrobial abilities in killing bacteria? I was thinking since that coating would be on the copper, there would be ...
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Does correct bond lengths and angles imply that water is in a potential minimum?

So I come from the math community (so please disregard my ignorance on the topic). If I have a water molecule and write the potential energy surface associated with it, my understanding is that I will ...
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Why does my drierite turn bright bright blue, instead of pink?

Drierite a brand name of a commonly-used, calcium sulfate-based dessicant in many chemistry labs. The lab I work in has a dessicator box we use to store hygroscopic materials. It isn't a a true dry ...
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1answer
59 views

How can water below a pH of 7 still be alkaline?

Alkalinity is a measure of the water's ability to neutralize acidity and is expressed in levels of bicarbonates, carbonates, and hydroxides. How can water that is slightly acidic, e.g. 5.5-6.5, still ...
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Why does a spur of ice sometimes appear when freezing water in my freezer

From time to time, a long spur of ice grows on one “cube” of my ice cube tray. It’s quite slender, about 3mm or 1/8 inch at the base tapering to about 1mm at the tip, but it’s about 30mm or over 1 ...
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1answer
51 views

How to read mutual solubility curves?

Came across a few graphs that represent the mutual solubility of two compounds, for eg, solubility of KCl, and NaCl with H2O. On these particular graphs, I can see Y axis as gms/100ml of KCl, on X ...
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For what chemical purpose did soldiers in WW2 carry small ion exchange resin columns in their survival kits?

My textbook [Chemistry Live, Declan Kennedy] states that ''During WW2 small ion exchange resin columns were part of a soldier's survival kit.''. I can't find any further info about this online or ...
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4answers
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Any idea why tap water goes stale overnight? [duplicate]

We have great tap water here in Hungary. My only problem that it goes stale overnight sometimes in some glasses or sometimes even the 2L water boiler has this problem too. But microbes cannot resist ...
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1answer
141 views

Order of solubility of sodium halides and potassium iodide

Order the following ionic compounds in decreasing order according to their ease to dissolve in water. a) NaBr; b) KI; c) NaF; d) NaCl. d > a > b > c a > b > c > d b > c > d &...
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Material Properties Dealing with “Wetting”

I am designing a rain device, and I am interested in a set of common metrics / standards for determining how something gets "wet". (1) Is there a "water absorbance" metric for ...
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1answer
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When converting between a hydrated electrolyte amount in mass and in milliequivalents (meq), why are the water molecules taken into account?

A textbook I'm reading called "Ansel's Pharmaceutical Calculations, 13th edition" defines the milliequivalent (meq) thus (p. 187): This unit of measure is related to the total number of ...
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1answer
71 views

How to differentiate hydrous and anhydrous compound? [closed]

For an experiment, my teacher gave me containers of hydrates and their corresponding anhydrous compounds, but I have a feeling that for one of the compounds she switched the hydrate and anhydrous ...
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2answers
205 views

What is intermolecular distance in water? [closed]

I am wondering what is an average intermolecular distance in liquid water (say under normal pressure and room temperature). I need just order of magnitude. A reference would be helpful.
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1answer
61 views

Why does matter have spaces between them? [closed]

If you mix sugar Crystal in a glass of water and mix it well, the level of water will not rise.The reason they say is that matter have spaces between them.If matter have spaces between them , How ...
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1answer
78 views

What makes the enthalpy of hydration of calcium chloride dihydrate unique? [closed]

I have recently done an experiment in an attempt to find the relationship between the water ratio in a hydrate and the enthalpy of hydration, and my results showed a correlation, but an anomaly for ...
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Aluminum Monoacetate Solubility in Aqueous Medium?

Does anyone have access to the aqueous solubility value of aluminum monoacetate? I would expect it to be slightly soluble but I've searched the internet and haven't found any solubility values. : /
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1answer
87 views

Why is RO water more corrosive?

According to several articles from the American Water Works Association, permeate from RO should be stabilized in terms of pH and hardness to avoid corrosion of the distribution piping. How does ...
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1answer
51 views

Does hot water dissolve Copper more than cold water?

I read from WA state dept health https://www.doh.wa.gov/portals/1/Documents/pubs/331-178.pdf that hot water disolves copper more copper than cold water. Use cold water for drinking and cooking. ...
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48 views

When does copper leach to water? Conflicting faqs [closed]

I have heard conflicting reports: Copper leaches to water only when the water is high in acid or the Copper is corroded. Copper leaches to water any time, especially when it is new copper or the ...
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449 views

Explanation for a basic decomposition of water experiment

My son is trying to write a conclusion for a basic decomposition of water experiment using a 9 V battery (with a test tube placed over each terminal) placed inside a salt water solution. The results ...
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1answer
28 views

Why does ink form tendrils on wet paper [closed]

When a drop of ink or watercolour paint is placed on wet paper, rather than uniformly diffusing in all directions it forms tendrils which rapidly expand out from the spot. Why is this and what is the ...
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43 views

What is the most exothermic reaction with water? [closed]

What substance reacting with water at room temperature and atmospheric pressure produces the most heat (per mole)? Does anything beat fluoroantimonic acid?
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2answers
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What are the properties of water in glaciers? [closed]

Does water from glaciers have many minerals (hard water) or would it be considered pure or distilled water?

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