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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27 views

Carbonic acid in pure water

In order to calculate the pH of pure water which is exposed to the atmosphere, we assume that the total concentration of carbonic acid in pure water is equal to the sum of dissolved carbon dioxide and ...
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Deposition of saturated solution and affect of evaporated water

20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of ...
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Effect of water vaporation on saturated solution

At a high temperature, water is evaporated from the saturated solution by heating. What is the solution losing exactly by the fact that the water left the saturated solution? Does it affect its ...
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1answer
25 views

The formation of ice crystals on/in frozen food that has been defrosted and then frozen again

I made a mistake. I put my ice cream in the refrigerator instead of the freezer and left it there for a night. I realized my folly the next day. I put it in the freezer. When I took it out, I noticed ...
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1answer
47 views

Must a desiccant be made anhydrous before it can be used for drying?

I'm writing about the treatment of methane gas, and in one part of the process, the methane gas is dried in a tank called a scrubber. Here, a desiccant called triethylene glycol is used. Thinking ...
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Real life implication for my experiment

My experiment is basically trying to find the relationship between the ratio of water in hydrated compounds (such as $\ce{Na2CO3·10H2O}$ or $\ce{CuSO4·5H2O}$, where the ratios are $1:10$ and $1:5$) ...
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3answers
566 views

What is the equation for the reduction of water? [closed]

I'm a grade 12 student trying to understand redox reactions. What's the equation for the reduction of water? The back of my textbook says: $\ce{2H2O + 2e- -> H2 + 2OH-}$ I get that this makes sense,...
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1answer
54 views

How much D2O is in Vienna Standard Mean Ocean Water?

I'm curious how much $\ce{D2O}$ (heavy water) is in Vienna Standard Mean Ocean Water. I am interested in $\ce{D2O}$ molecules and not $\ce{HDO}$/$\ce{D+}$/ $\ce{DH2O+}$/$\ce{D2HO+}$/$\ce{D3O+}$ or any ...
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Does drinking “reboiled” water actually present any health risks? [duplicate]

I have seen evidence in popular media that drinking "reboiled water" (water that is brought to a boil that cools down and then is boiled again) is unsafe or presents an increased chance of ...
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Why doesn't pure water conduct when it dissociates? [closed]

Sorry if this is an obvious question. I am told water dissociates, one product of which is negatively charged hydroxyl ions. This makes sense, but then why doesn't pure water conduct electricity? ...
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1answer
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Are all gases equal in their ability to carry with them lower volatility matter at a given temperature? [closed]

As we all know water is a great solvent in it's liquid form relative to other substances. I wonder however how it performs as a gas relative to other stuff. Does anyone know how well steam carries ...
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Are there limits to waters energy absorbtion capacity

I have a system where I heat water in a flask. The water vapor generated is condensed and returns to the original container (not a pressurized system, but condensation system is efficient enough that ...
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What would happen if water is to flow through a microchannel where its top is hydrophilic and bottom hydrophobic?

What would happen if water is to flow through a microchannel where its top is hydrophilic and bottom hydrophobic? If an external pressure is applied, for example, a syringe pump is used, it is ...
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2answers
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Does changing the electrolyte concentration in the electrolysis of water affect the speed that hydrogen gas is produced at the cathode?

I am currently completing a Year 12 Extended Practical Investigation. Due to the lock-down restrictions we are unable to complete our own practical experiment and have been given sample answers with ...
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Solubility Product, and it's relation to solubility

In order to remove temporary hardness of water, it is boiled. On boiling, while Ca(HCO3)2 gives CaCo3(ppt.) , Mg(HCO3)2 gives Mg(OH)2(ppt.). According to my book precipitation of Mg(OH)2 occurs due to ...
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1answer
29 views

Which salt is a surfactant and lowers the surface tension of the water? [closed]

I am doing my experiment on the surface tension of the water. How to show the decrease of surface tension of water with the increase in the concentration of salt? Is there any salt that lowers the ...
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1answer
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How does the surface tension of water decrease with an increase in the concentration of NaCl?

Can anyone help me with the theory of surface tension? My chemistry experiment is related to the surface tension and concentration of NaCl. I am confused about my hypothesis. On the internet, I found ...
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102 views

How much 'stronger' is water vapor than carbon dioxide, molecule-per-molecule, over the course of a day, in terms of global warming potential?

I have read, many times, that water molecules are far more effective than CO2 molecules at trapping heat... But, the 'relative G.W.P.' value of water vapor (or its 'radiative forcing') is not listed ...
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1answer
27 views

How is the hydration state of a chemical related to its adsorption of water?

I am trying to understand adsorption and hydration states better, and I was thinking about the different hydration states of calcium sulfate - anhydrous ($\ce{CaSO4}$), hemihydrate ($\ce{CaSO4*1/2H2O}$...
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1answer
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Turning sun into water [closed]

I don't know if this question belongs here or on physics stackexchange, but I believe it leans more towards this site. A friend of mine had a strange but funny shower thought. He said: "What ...
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55 views

Freezing point of solution of Water, Ethanol and Sugar (aka, Limoncello)

I'm looking for a diagram of the freezing point of a water solution depending on its content in sugar and ethanol. More colloquially, I want to know how to balance alcohol and sugar so that my ...
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1answer
71 views

Latent heat of vaporization/evaporation

It's the amount of heat required for liquid ---> gas phase change of a substance at it's Boiling point. But my question is, does providing energy equivalent to latent heat of vaporization to a ...
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1answer
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Karl Fischer Titration simple explanation

I'm looking for a simple explanation how the Karl Fischer method to determine the content of water works. I'm not a chemist but an engineer from an electronic-physical field and my chemistry courses ...
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1answer
40 views

What is exposed in the surface tension of water?

(I guess) I understand the covalent bonding of water and the hydrogen bonding of water between two different molecules, but I would like to know which part is the part that that exposes itself to the ...
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Why does the solubility of haloalkanes in water decreases as the length of the carbon chain increases?

Due to the polar halogen-carbon bond in haloalkanes, they are more soluble than hydrocarbon in water. But the solubility is still very low because the overall influence of the dipole-dipole ...
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1answer
55 views

What happens when you put a battery in saltwater? [closed]

If somebody puts a battery in a salt solution, what path do the electrons take?
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Ice geometrical shapes [duplicate]

https://en.wikipedia.org/wiki/Ice https://www.google.com/search?q=ice&prmd=inmv&sxsrf=ALeKk028fJvrUcWLWu8EV-KsRGuiw0iWWw:1596098668929&source=lnms&tbm=isch&sa=X&ved=...
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1answer
51 views

Leaving Group Tendencies in Amide Hydrolysis

When we do hydrolysis of amides in basic conditions, we come across a mechanism in which the $\ce{OH-}$ ion attacks the carbonyl forming an intermediate as given in the photo: When the carbonyl gets ...
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What acids, solvents is lithium-6 fluoride soluble in (other than HF)?

$\ce{LiF}$ is quite insoluble in water, and I'm trying to use some water-soluble acid or solvent to dissolve $\ce{^6LiF}$ (95% enriched) in. I'm not a chemistry person, I'm a radiation detection ...
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1answer
64 views

Amine vs Amide Solubility

I had a question regarding the solubility of amines and amides. I was looking into the solubility of butanamide and n-Butylamine, and it turns out that whilst butylamine is miscible in water, the ...
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1answer
34 views

How to accelerate the evaporation of water at temperature below 5 °C? [closed]

How can we make the water to evaporate at low temperature? Does addition of high evaporating solvents help or decrease in the hydrogen bonding by addition of solute will help? Is there any other ...
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1answer
205 views

Why is a drop of chloroform stretched/pulled apart on a water surface?

I distributed drops of chloroform (with a lipid in them) on water (in a Langmuir-Blodgett trough). The chloroform drops form a layer on the water (so that the lipids are distributed on the water ...
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1answer
69 views

Does the depth of a lake affect how quickly its water is evaporated? [closed]

Suppose there are two freshwater lakes, each with identical surface areas and circumferences. One lake is 1 ft deep and the other is 20 ft deep. Although they exist in nature, lets assume they are ...
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1answer
54 views

How can I measure the scale in water?

I have hard water in my house. All the taps have tartar around. It generates some problems in some of my home appliances so I have bought polyphosphate salt but when I boil water I don´t get the ...
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1answer
106 views

Reaction Of Carbonic Acid With NaCl [duplicate]

I was just wondering if it was possible for anyone to specify what reaction conditions are required for the reaction between $\ce{H2CO3}$ (Carbonic Acid) and $\ce{NaCl}$ (Sodium chloride)? Does this ...
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1answer
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Can elemental silicon react with water at room temperature and pressure? [closed]

Free silicon is not found in nature (in water, it might be present in the form Si(OH)4). So how is Si(OH)4 formed? Is there any possibilities of direct reaction with water?
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Bleach in water only good for one day? [closed]

In this time of COVID-19 our establishment is being told by government sources to spray down surfaces with a 9:1 water bleach solution, and then told to throw it out within 24 hours. What makes it ...
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1answer
57 views

How much time for a water molecule in pure water to reach the top of a glass of water?

I have a curiosity to know how long it will take for a water molecule to move a certain distance in pure water. I can put it simply as how much time for a water molecule to travel the whole length of ...
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1answer
91 views

How does the entropic force arise within the hydrophobic effect?

I know that the hydrophobic effect is usually explained by the entropic effect originating from the disruption of hydrogen bonds between molecules of water and the nonpolar substance. The hydrogen ...
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28 views

Is it possible to determine if a substance can dissolve in water just by looking at its chemical structure? [duplicate]

Is it possible to determine if a substance can dissolve in water just by looking at its chemical structure? For example, how am I supposed to know if $\ce{NaHCO3}$ and $\ce{Na2CO3}$ can dissolve in ...
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1answer
35 views

Why does Sodium Hydrogen Sulfate (Sodium Bisulfate) produce moisture?

In my chemistry lab, I have a vial of Sodium Hydrogen Sulfate (Sodium Bisulfate). I've noticed that when I take a spoonful using a spatula, the spatula gets covered in many tiny droplets, and the lid ...
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1answer
140 views

Does CO2 dissolve in water?

First of all not a homework question, but one day it suddenly popped into my head while opening a bottle of soda and accidentally leaving a glass out for a while. I get that $\ce{CO2}$ in water is not ...
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28 views

Why does ethanol have a stronger cooling effect on the body than water? [duplicate]

Why does ethanol have a stronger cooling effect than water (i.e. it feels cooler when dropped onto one’s hands) even though water has a higher heat of vaporization compared to ethanol? If we drop a ...
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1answer
55 views

1.0 g of AlCl3 is added to 100.0 ml of water. What would be the resulting pH?

$1.0\ \mathrm g$ of $\ce{AlCl3}$ is added to $100.0\ \mathrm{ml}$ of water. What would be the resulting pH? I think the answer may be $4.022$ but I'm not certain. The reaction wasn't provided but I ...
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What's the most effective way to reliably trigger and observe hard water scale buildup at a micro level?

We live in an area that's got some really hard water. It's so hard that it kills most of the fish we try to care for in our aquariums and shrimp?... forget it. While this is sad and challenging for ...
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0answers
30 views

Surface Tension of Water and Breaking through that surface tension

I know that the high surface tension of water makes it relatively more difficult for light objects to break through the surface (i.e. it's why insects can "walk" on water). So that seems to work when ...
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1answer
65 views

Are phase transitions reversible when performed at supercooled temperatures?

For the state transition of supercooled water to ice, is the process reversible? I wonder this because I want to know if I can use entropy change of the universe is 0. If it isn't reversible, how do ...
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1answer
58 views

Creating a 10 ppb Lead Nitrate Solution

I’m trying to make a 10 ppb Lead Nitrate solution as part of a concentration calibration step for a Beer Lambert’s Law experiment. I plan on performing a dilution in three steps. The calculations have ...
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1answer
166 views

Confusion about Titration Formula [closed]

When performing a titration of a monoprotic acid and a monoprotic base, water can not be added to the titrant but water can be added to the analyte. To prove this statement to myself, I decided to ...
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1answer
62 views

Thermodynamic model of inclusion process of alpha-cyclodextrin

I have a question about thermodynamic model of inclusion process of CD, published by Tabushi (DOI: 10.1021/ja00471a043). Here, in 3rd step, action is described as: "An apolar solute (guest molecule) ...

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