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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639 views

How was water formed if oxygen and hydrogen exist as molecules?

I have learnt that both hydrogen and oxygen exist as molecules. If so how was $\ce {H2O}$ formed? In water there is two hydrogen molecule and one oxygen atoms but how is this possible? Oxygen only ...
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1answer
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Boiling point elevation does not depend on the solute? [on hold]

I've recently carried out an experiment trying to measure the boiling point elevation of water after adding 5M of NaCl and KCl. Although for some reason, KCl solution started boiling around 90 degree ...
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Oxygen Extraction From Water ( Conversion ) How many Oxygen is produced from 1 liter of water? ( Liters of air ) [on hold]

How many Oxygen is produced from 1 liter of water? Answer is needed to be convert in ( Liters of air ) e.g Human consume 7 to 8 liter of air in one minute.
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Synthesis of dibasic calcium phosphate dihydrate [on hold]

How to prepare dibasic calcium phosphate dihydrate $(\ce{CaHPO4·2H2O})$ from anhydrous salt $(\ce{CaHPO4})$? I'm specifically interested in a dihydrate, not mono- or trihydrate.
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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 ...
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N-methylacrylamide (NMAM) vs N-isopropylacrylamide (NIPAM): expected difference in effects on water structure

The only difference between these two is the group attached to the Nitrogen: in NIPAM, it's isopropyl, while in NMAM it's methyl. In a study on aqueous NIPAM, it was shown that the isopropyl groups ...
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1answer
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Cleaning an overhead water tank using Alum or other chemicals?

Alum is generally used in water tanks to settle down solid impurities. Since it contains aluminium I suspect it to be toxic to humans. So are there any safe chemicals to clean large overhead tanks ...
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1answer
42 views

Will charcoal briquettes (not activated) absorb water out of the air in the house in a subtropical climate?

I live in Florida, an incredibly wet environment where it's very difficult to get moisture out of house without using a dehumidifier 24/7, which is too expensive. Would charcoal briquettes be of any ...
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3answers
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Are all volatile liquids combustible?

I realized that liquids like petrol, kerosene and even perfumes are combustible when they are volatile. Could that be the reason why water is not combustible is because it is not volatile? Are ...
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2answers
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What is the formula for evaporation rate of water?

I did my own research, and according to The Engineering Toolbox,the formula for the evaporation rate of water is as follows: $g_\mathrm h = \Theta A (x_\mathrm s - x)$ $g_\mathrm h$ = amount of ...
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1answer
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Why does boiled water have a different taste as compared to cool water? [closed]

I have noticed it frequently and decided to check with some of my peers and friends about this and they too have felt such a thing. The taste comparison occurs after the boiled water is cooled down to ...
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1answer
36 views

Combustion byproducts

I'm designing a system which will heat up water by burning natural gas which is commonly available. I would like to have a slow flame because water will need to reach 70 degrees C and stay there. ...
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1answer
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Water molecule bent shape and electron configuration [closed]

The hydrogen atoms in a water molecule are negatively charged, so they should repulse each other completely due to the electromagnetic force, forcing the hydrogen atoms to be on opposite sides of the ...
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1answer
181 views

How do I convert this ion exchange capacity into water softening capacity?

I am researching for an extended experimental investigation into methods of water softening. One such method is the use of ion exchange resin. I have contacted the supplier of the resin for its ...
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179 views

Numerical related to crystallisation of water below its freezing point

Question: There is $16\ \mathrm g$ of pure water in a container at temperature $-20\ \mathrm{^\circ C}$. A small piece of ice is added to start crystallization. Amount of water in container when ...
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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 ...
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320 views

What fraction of the vapour in electronic cigarettes is water?

Not a chemist but looking for an answer I can understand. Electronic cigarettes use propylene glycol and/or vegetable glycerin as a base liquid. This is heated and vaporized at a low temperature (my ...
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Can we break the covalent bonds of water molecules using resonance frequencies?

Can we break the covalent bonds of water molecules $\ce{H2O}$ using resonance frequencies? What is the wavelegth of the water's molecule? Can we create a vibration like this and use it to separate ...
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1answer
81 views

Is Phosphate (PO4 3-) solube in water? [closed]

Josh~ Superphosphate is used instead of just phosphate because superphosphate is a compound whereas phosphate is an ion. This means that phosphate must attach itself with a cation in order to give a ...
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1answer
3k views

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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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 ...
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1answer
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Using table salt as a way to limit humidity in an unoccupied house

We own a static caravan in the UK (Snowdonia region, so rainy and wet all year round, moderately cold winters) and we leave it unoccupied during Winter (Oct-Feb). We were advised of an apparently ...
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1answer
461 views

To extend the life of a cartridge razor blade, should the blade be stored in oil or alcohol?

I've read varied recommendations about extending the life of a razor blade. Some say should stick the blade in oil when not in use, others say in alcohol, others say in a bowl of rice or silica gel. ...
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How does boiling water affect its hardness?

Does boiling water reduce its hardness, or on the contrary, increase it? It seems there are ambivalent phenomena at play here: boiling will evaporate pure water, thus increasing the concentration of ...
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1answer
49 views

Temperature and pressure for three phase equilibrium of aqueous sodium chloride solutions

I am currently investigating the effect of adding Salt(NaCl) to water on its triple point. Let us assume the mass ratio of water to NaCl is $1:1$. I asked a similar question previously. But, I still ...
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2answers
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White creamy substance (not calcium) observed when boiling water is filtered through coffee paper filter

We have hard water from our well. It is filtered twice before boiling it: by the water filter and with a manual on-the-counter filter. When boiled in a clean kettle a white substance floats in the ...
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4answers
90 views

Dissolving sand (or something similar) in a bottle of water?

I would like to create an illustration to demonstrate something during a talk. The idea goes that there is sediment in a bottle of water that sits at the bottom until shaken up then adding another ...
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2answers
395 views

Can gaseous hydrogen and gaseous oxygen be compressed without reaction?

I'm looking into building a clean Bunsen-style burner (or rocket engine - I haven't decided yet). I will be using electrolysis to extract hydrogen and oxygen from water, but the apparatus I am ...
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What would superionic water ice look like?

Phys.org's Giant lasers crystallize water with shockwaves, revealing the atomic structure of superionic ice links to Nature Physics: Experimental evidence for superionic water ice using shock ...
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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 ...
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1answer
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Can the light reaction of photosynthesis happen spontaneous in pools of water?

I've just learnt that a part of the photosynthesis reaction is the light reaction, where sunlight is absorbed by chloroplasts, which then excites electrons to higher energy levels, allowing for water ...
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1answer
1k views

Why does ozone have such a large solubility in water?

At $25~\mathrm{^\circ C}$, the solubility of ozone is $109~\mathrm{mg~L^{-1}}$. This is $13$ times higher than the solubility of diatomic oxygen. What causes this?
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coffee concentrate and water separated after 2 hours. How/why?

I'm asking because this makes no sense to me and making sure I'm not stupid. I brewed 10 gallons of cold brew concentrate(TDS 12.2) and mixed it with 10 gallons of water. I moved 10 gallons of the ...
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1answer
34 views

Will sodium thiosulfate react with nitrate and/or nitrite ions [closed]

I am doing nitrate and nitrite quantification in raw water and treated water using a colorimetric method. The manufacturer of the instrument states that water with chloride will interfere with the ...
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2answers
42 views

Metering Device decreases pressure yet produces saturated liquid?

This question pertains to the change of state of liquid using a Metering Device as the refrigerant enters an Evaporator Coil of an HVAC system: The Metering Device takes liquid and then reduces the ...
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0answers
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Issue with evaporation rate of water

The evaporation rate of water (kg/s) is given by: $$g = \frac{P}{P_o} AΘ$$ Where $P$ is given in Pascals and $A$ is the surface area (in $m^2$) and $Θ$ is the empirical evaporation ...
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292 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 ...
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1answer
286 views

Can ideal gas law be applied to water vapour? [closed]

How to accurately estimate the molar concentration of pure water vapour at 298 K? Can ideal gas law be applied to water vapour to calculate the molar concentration?
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How do you remove lumps in reagents without contaminating them?

I think desiccating the powdered reagent would help remove lumps (at least in preventing lump neoformation) but would desiccation alone collapse all lumps in a powder (say KCl as it lumps easily), or ...
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2answers
93 views

Does adding solutes to water alter its triple point? [closed]

Does adding solutes to water alter its triple point? If yes, how do we find the new temperature and pressure of this point?
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491 views

Dry water using graphite

Dry water or "powdered water" is essentially a bunch of extremely small water droplets surrounded by $\ce{SiO2}$. Some time ago, I was messing around and mixed some powdered graphite with water. (The ...
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2answers
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Why is distillation not a viable way to separate ammonia from water?

Since the steam pressure of ammonia is higher than that of water, I would expect distillation to be a reasonable way of separating a mixture of both. However, in industrial applications known to me ...
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147 views

Do we consider the dissociation of water when dealing with ion concentrations of a solution?

One mole of hydrated copper(II) sulfate, $\ce{CuSO4 . 5 H2O},$ is dissolved in water. How many moles of ions does the solution contain? 1) 1 2) 2 3) 6 4) 7 The correct answer is 2. ...
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1answer
270 views

Reason of dissociation of water molecule in electrolysis

$\ce{H2O}$ molecule is dissociated into $\ce{OH-}$ and $\ce{H+}$ ions on reduction at the cathode in electrolysis. But what happens at the atomic level to $\ce{H2O}$ that proton and hydroxide ions get ...
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1answer
93 views

Reaction of potassium with water

In general, when we put potassium into water, it will produce potassium hydroxide and hydrogen: $\ce{2K + 2H2O ⟶2KOH + H2}$ However isn't the following reaction also possible? $\ce{2K + H2O ⟶K2O + ...
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1answer
785 views

How does chlorine in water evaporate?

Drinking water (e.g. from your home's tap) is spiked with chlorine, for an amount of just some ppm. Purpose of this operation is to kill bacteria, for our health. Background: chlorine in water is ...
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If carbon dioxide is non polar, why does it react with water?

I’ve read in many places that carbon dioxide forms carbonic acid with water since the carbon is partially positive and thus the oxygen bonds with it. But isn’t carbon dioxide in its entirety non polar ...
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1answer
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Mechanism of burning of hydrogen [duplicate]

So I was curious regarding a simple chemical equation : $$\ce{2 H2 + O2 -> 2 H2O}$$ You add heat to the system (i.e fire) and you get water vapor. I'm curious of understanding the mechanism, ...
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Why does H2O electrolysis produce O2 on the anode instead of H2O2

If the oxidation of $\ce{H2O}$ produces $\ce{OH-}$ ions and the anode separates electrons from them leaving neutral $\ce{OH}$ molecules, why don't they bind to each other covalently?
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2answers
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Plastic membrane that lets water in from the outside only?

I'm looking for a type of plastic membrane that would let water through it from the outside, but wouldn't allow water to escape once it's inside the membrane. Ideally available in a roll. Does such ...