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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Does nitrogen oxide react violently with water? [duplicate]

We are going to clean an ozone generator. I understand the residue will be nitrogen oxide. When we rinse, is the mixing of water with the nitrogen oxide an exothermic or violent reaction?
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Why is NaCl so abundant in the ocean [closed]

Why is sodium chloride far and away the most abundant salt dissolved in ocean water. Its two constituent ions do have a very high frequency in the crust of the earth but they are far from the most ...
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How can I save an EEM file on a Fluoromax4?

I'm trying to run excitation-emission matrices on some water samples, but I'm running into some software issues that the manuals aren't helpful for. In order to use R studio to extract my data, I need ...
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How can I set up and process my excitation-emission matrices properly?

I'm running EEMS on some water samples on a Horiba Fluoromax 4 spectrofluorometer. Method below. $\pu{240-580nm}$ emission, $\pu{5nm}$ interval, $\pu{1nm}$ width. $\pu{240-480nm}$ excitation, $\pu{...
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183 views

Volume of Oxygen Produced By Electrolysis of Water [closed]

I am trying to estimate the volume of oxygen that will be produced by electrolysis of water at normal temperature and pressure with a current of $\pu{50 A}$. The following is my calculation: The ...
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A solution is cloudy at lower concentration and becomes clear at higher concentration. Why?

This might be just an "everyday life science" question. I am a university professor but not in Chemistry so please educate me. Today I was adding some floor cleaner formula to water as ...
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is electrolysis of water less efficient with warm water? E.g 40, 50, 60… °C

I see there is High-temperature electrolysis which is a whole different animal than room temp electrolysis. I want to know if electrolysis of lukewarm water will behave much differently. My guess is ...
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On the molybdenum(III) oxide-catalysed oxidation of alkanes to carbonyls

The following reaction is specified in my notes; $$\ce{CH4 ->[Mo2O3, \Delta]HCHO}$$ The intermediate steps involve the dehydration of an alcohol to yield the final product. Wouldn't this only work ...
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Why does the addition of heavy water cause OH and NH peaks in NMR spectra to disappear?

When $\ce{D2O}$ is added to a sample, the OH and NH peaks in a $\ce{^1H}$ NMR spectrum disappear. This is the basis of (for example) the $\ce{D2O}$ shake test, and is also the reason why peptide/...
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Is there a relation between polarity of molecules and their electric susceptibility?

So it is written in our text that electric susceptibility ($χe$) (the response of say water molecules in the presence of an external electric field) is related to the molecular behaviour of various ...
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Finding the charge passed in electrolysis of water using volume of hydrogen released [closed]

During the electrolysis of water we have gotten $\pu{10 dm3}$ of hydrogen. Temperature was $\pu{0 °C}$ and pressure was $\pu{101325 Pa}$. What charge has passed trough the electrolysis article/joint? ...
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Hydrogen peroxide on damp clothes left out in the sun [duplicate]

Somebody told me that sunlight is a good bleach for clothes because leaving damp clothes outside in the sunlight will turn some of the water into hydrogen peroxide. Is this true. If yes, then why can'...
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Which process would separate the mixture of toluene, cyclohexane and water?

toluene: $\ce{C6H5-CH3}$ cyclohexane: $\ce{C6H12}$ I think that answer would be: Toluene and cyclohexane do not dissolve in water (since they are nonpolar), so I would first separate the water from ...
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CCSD and CISD size consistency problem

I have performed a Gaussian16 calculation to explore the size-consistency problem for the CISD and CCSD methods. The system I am studying is the water dimer and the results are not what I expected at ...
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Electrolysis of water using different kind of electrode and electrolyte safest as possible for splitting demonstration

I am planning to electrolyze water for an experiment. However, I have limited resources and want to do it as safely as possible The resources that I have: $\pu{12 V}$ DC battery Graphite (in the ...
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How does the relationship between carbonate, pH, and dissolved carbon dioxide work in water?

Fish keepers use a table like the one below to determine dissolved $\ce{CO2}$ by observing the color of a pH indicator in water with a known concentration carbonate solution (typically 4 degrees KH ~= ...
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Milliliters of NaBr when changing molarity [closed]

I was very confused by this problem. I was able to get the molarity, but I wasn’t certain how to go from there: If $\pu{2.60 g}$ of $\ce{NaBr}$ is dissolved in enough water to make $\pu{160.0 mL}$ of ...
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Will water interfere with an in-situ XAS measurement of the Pt L3 edge during OER on a water electrolysis cell?

I am trying to design a cell for an in-situ experiment. As much as possible, I was hoping to be able to do it on a PEM MEA rather than on a half cell immersed on an electrolyte. I am thinking that ...
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29 views

Hard water filtration

Why does hard water have to pass through the cation exchange resin first followed by the anion exchange resin? Why can't it be the other way around?
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What is the heaviest possible water using oxygen and hydrogen isotopes, and what might it's physical properties be? [closed]

After a cursory internet search, it appears to me that Hydrogen-3 (a part of Tritiated Water) is the heaviest stable* hydrogen isotope. Oxygen-21 is the heaviest isotope of Oxygen with a half-life of ...
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Can potassium carbonate be used to calibrate hygrometers?

Context: In the process of trying to calibrate a number of hygrometers, with Sensirion MEMS electronic sensors, I came across the method of using wet salt: an airtight container will stabilize at a ...
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What is the difference between atom and nucleus? [closed]

Atomic nucleus-The atomic nucleus is the small dense region consisting of protons and neutrons at the center of an atom discovered in 1911 by EARNEST RUTHERFORD. Atoms are made up of a positively ...
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Do water filters expire even if underused? [closed]

This filter rates a 3 month lifespan with 1210 liter capacity, but I expect to filter only 300 liters in 3 months. Is it still expired after 3 months - if so, why? What degrades a filter while it's ...
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Calcium chloride as a drying agent for solutions

I'm aware of the reaction Calcium chloride has with water vapour and how it can therefore be used as a good and inexpensive drying agent but could that be applicable for solutions? For example if ...
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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