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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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5
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3answers
346 views

Does distilled water still have ions in it? Does deionized water lack ions, but still have other "stuff" in it?

This isn't a question about the difference between Deionized and Distilled water, my hope is that for once it's actually a chemistry question related to this topic. Distilled water is created by ...
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0answers
22 views

How to make my water destillery most effective?

I got a destillery for water with a capacity of 10l and a get the most of a spiral cooler in a 1l cooling pot mounted on top. I'm happy with the efficiency, however there's always room for improvement ...
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0answers
32 views

How hot does a fire have to be before water worsens it instead of helping (i.e. splits)? [duplicate]

So i'm not sure if I have this right but anything will melt/burn/decompose/split apart with ENOUGH heat, correct? So, at what temperature does water go from being helpful for putting out a fire (H20, ...
2
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0answers
16 views

Is there a difference in electrolsys rate limiting effects between electrodes of different area if one reverses the electrical polarity?

If one has two concentric stainless steel tubes with the small one being 1/2 the circumference and inside the other, and KOH for the electrolyte, then given the different surface areas between the ...
-4
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1answer
78 views

I mix table salt and baking soda with water to make mouth rinse, and leave them for several days. It started to form precipitation, and a bad odor [closed]

I mixed 2 spoons of baking soda with 1 spoon of salt and mixed them with water (but not mixing totally) and left them for several days. At first I saw some bubble but the water was clear, but then it ...
1
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0answers
39 views

Water density in the calculation of the ionic product of water

In 2019 the International Association for the Properties of Water and Steam released this document for the semi-empirical calculation of the ionization constant of water: http://www.iapws.org/relguide/...
-1
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1answer
65 views

Adding H2O2 in water does what to the pH of the water?

Not looking for numbers (unless required). I searched for this question on Google and found irrelevant results, with only the following link of some use but it doesn't appear to answer my question (...
2
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1answer
110 views

Mission: Impossible? Hydrocarbons in an aqueous liquid (e.g. humulene in beer)

Your mission, should you decide to accept it, is to describe how hydrocarbons can be stably mixed into a water-based liquid such as beer, as in this question. According to the usual textbook wisdom, ...
2
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0answers
46 views

Hazardousness of Chlorothalonil & metabolites in shower water? [closed]

Recently it came out, that in some parts of Switzerland (where I live), there is Chlorothalonil & metabolites/breakdown-products of it in the drinking water. Yikes. Problem is, chlorothalonil ...
4
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1answer
49 views

Computational determination of the diagram of molecular orbitals of a polyatomic chemical species

A diagram of molecular orbitals for $\ce{H2O}$ would be as follows: The above diagram has been constructed qualitatively following the steps that I have been instructed in various classes on this ...
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2answers
69 views

Can stainless steel be electrically insulated with (oven-dried) Sodium Silicate Solution?

Can I electrically insulate stainless steel by painting Sodium Silicate solution on it and heating it to 200C for 30min or so? The solution should be conductive, and I've been told (to be verified) ...
1
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1answer
106 views

In an open system, can water vapor escape into the atmosphere before reaching the boiling point? [duplicate]

In a closed system, water vapor would have nowhere to go and atmospheric pressure would not be a factor. It would reach dynamic equilibrium with only water vapor. But in an open system, I think that ...
2
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0answers
51 views

What happens to water and oxygen produced due to dissociation of nitric acid? [closed]

Nitric acid is yellow in colour due to the dissolution of nitrogen dioxide gas. The nitrogen dioxide is obtained due to thermal dissociation of a portion of nitric acid: $$\ce{4HNO3 -> 2H2O + 4NO2 +...
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0answers
53 views

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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0answers
31 views

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 ...
3
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0answers
38 views

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{...
0
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1answer
475 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 ...
3
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2answers
123 views

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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0answers
35 views

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 ...
4
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1answer
62 views

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 ...
2
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0answers
97 views

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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0answers
54 views

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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1answer
99 views

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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0answers
60 views

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'...
0
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1answer
272 views

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 ...
3
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0answers
57 views

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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1answer
60 views

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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2answers
170 views

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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2answers
53 views

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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0answers
14 views

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 ...
2
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1answer
35 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?
3
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1answer
66 views

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 ...
4
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1answer
62 views

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 ...
-5
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1answer
252 views

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 ...
-1
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1answer
41 views

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 ...
1
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0answers
65 views

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 ...
0
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0answers
18 views

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 ...
2
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0answers
32 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.&...
1
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1answer
40 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, ...
-1
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1answer
30 views

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 ...
5
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0answers
54 views

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
77 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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0answers
76 views

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 ...
0
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3answers
78 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-...
8
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4answers
812 views

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 ...
0
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1answer
52 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 ...
2
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3answers
529 views

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 ...
4
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0answers
65 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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0answers
46 views

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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1answer
111 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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