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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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What happens when para-water ice is suddenly melted?

Background (hydrogen) In the case of recently liquified hydrogen (which is quite cold of course) it must be re-equilibrated before loading on to a rocket as fuel to avoid a sudden exothermic ...
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179 views

Conductivity measurements of demineralized water - Unexpected results. Looking for explanation

I'm trying to measure the conductivity change of demineralized water over a few days. But I get results I can't explain. Setup This is the circuit and cell I'm using: Where $R_x$ is the ...
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1k views

How to dissolve slime jelly?

Suppose I have a small kid that had two cans of slime jelly (a Jelly made of water, glycerin, thickeners, dispersant, flavorings and pigments). And that two cans were inside a backpack, and somehow ...
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44 views

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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82 views

Does increasing # of hydrogen bonds decrease the strength of these bonds?

I saw the question, "Is the strength of hydrogen bonding greater in hydrogen peroxide or water?" and it reminded me of a question I had about hydrogen bonding: If an oxygen on a water has a hydrogen ...
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121 views

Why does pKw first decrease but eventually increase when temperature rises?

I understand the initial decrease in pKw. $\ce{Heat + H2O (l) <=> H+ (aq) + OH- (aq)}$ Temperature increases, reaction shifts to the right, so $\ce{H+} \text{ and } \ce{OH}$ ...
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47 views

Is there anyway to derive the number of water molecules in a hydrated salt, given just the formula for the anhydrous salt?

Is there anyway to derive the number of water molecules in a hydrated salt, given just the formula for the anhydrous salt? That's pretty much it. If not, why? For coordinated water, my guess is ...
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72 views

Can this happen to superheated water?

Superheated water refers to water that is heating well beyond its usual boiling point under extreme pressure. This cause it to display anomalous property. I noticed that as temperature increases, so ...
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64 views

Should I add more of a trihydrate chemical to a solution if recipe calls for hemihydrate?

I am running phosphate by the ascorbic acid method (SM 4500-PE, PDF), and making the antimony potassium tartrate reagent. Standard methods uses $\pu{1.3715 g}$ of $\ce{K(SbO)C4H4O6 * 1/2 H2O}$ per $\...
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76 views

Can someone help me finish this reaction?

This question revolves around sodium percarbonate (https://en.m.wikipedia.org/wiki/Sodium_percarbonate) and its reaction with sulfuric acid. I didn't find anything, so I tried assembling it myself. ...
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438 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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425 views

The Health Effects of Alkaline Ionized Water?

I came across alkaline ionized water as my aunts bought a system called Kangen Water from Enagic Inc. The water produced by this system is claimed to contain smaller water clusters (4-6 molecules) ...
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How to break down soap and detergents?

I am building a greywater harvesting system. It is a 3-stage system: The 1st stage breaks down soap and detergents. The 2nd stage filters the water. The 3rd stage pumps water out of system. What ...
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1k views

Does the temperature of water change during electrolysis?

Applying an electric potential to impure water splits water into its constituents H/O. Does the temperature of the electrolyte change during this electrolysis?
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160 views

How do xanthan gum and other hydrocolloids work?

Does anyone know what causes things like xanthan gum to make water into a slimy substance on the molecular level?
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396 views

Calculating total volume mixing NaCl and water

I'm (as a non chemist) trying to calculate the the volume of a NaCl solution. The problem is that I know the volume of water prior to mixing in NaCl, but I want to know the volume of the solution ...
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28 views

Gel in water machine

I have a hot and cold water dispensing machine from my water company. I use 5 gallon water jugs delivered ever 3-4 weeks. The machine has a tank in it where water is kept cold until dispensed by ...
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72 views

How to prepare a water sample for photometry

The purpose of measuring N P K Ca Mg S is to determine the amount of material consumed by different types of plants in different periods. The initial solution, which is prepared as a nutritious ...
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218 views

Cheap spectral analysis to analyze water quality

I need some guide about spectrometers I saw a lot of DIY spectrometers to analyze light. Does anyone try to use those DIY spectrometers to analyze water? To detect heavy metals? or a chemical? or ...
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706 views

Is there a food-safe hydrophobic liquid with a substanially higher denisty than water?

Requirements In short, I am looking for a fluid that meets these criteria: Hydrophobic Denser than water Low viscosity Food safe Background We are working on adding a pool and designing a backyard ...
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132 views

What is the ideal temperature and pressure to crack water?

Using sun mirrors and solar cells for electricity. What temperature, pressure and voltage ideal for cracking water. Source: NPR Source Would it take more or less electricity to crack water under ...
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61 views

Hydrogen Bonding in Water (MO theory)

Valence Bond Theory tells us that each of the “sp3” (in reality, 44% s character) oxygen line pairs in water can act as electron donors, but observing the MO diagram for water tells us that the 2 non-...
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30 views

Is there a non toxic moisture indicator that can be applied on a wall?

I am looking for a substance that could serve as an indicator for a risk of mold growth, e.g. by a change of its hue. Cobalt chloride is both irritant and carcinogenic so is not an option. I've found ...
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96 views

How much energy water “captures” at it evaporates in room temperature?

As explained in Why does water evaporate spontaneously at room temperature despite ΔG > 0? water evaporates in room temperature because partial pressure of water is less than "standard" conditions ...
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488 views

Relationship of CO2 in water

We have an evaporative cooling system here at the power plant that uses city water. The water is pumped up and cascades down across a filter media cooling the intake air to the gas turbine. This is ...
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88 views

What kind of water would Oxygen-15 and tritium create?

I've recently become interested in chemistry, and have some questions about water. I've heard of semi-heavy, heavy, tritiated, and oxygen-heavy water. However, what about various combinations of ...
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46 views

Color Visible in Large Quantities of Ethanol

I am currently writing a sci-fi novel and have come upon a rather ponderous question that I have thus been incapable of discerning an answer for. If a planet were to have oceans composed not of water, ...
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139 views

Why is it difficult to measure the pH of environmental water samples accurately (near 7)?

I've read in several places (edit: 1, 2, 3, 4, 5, 6, 7, 8. 9, 10, 11, 12) that there are many practical factors that make accurate pH measurements of roughly neutral environmental water samples more ...
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35 views

Purple rinse water

After forming a white substance while on the stove, I rinsed the Pyrex pot under tap water (from a well), whereupon the water in the pot turned purple. Why did this happen? Iron and sulfur are ...
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52 views

Behaviour of oleophobic and hydrophobic object in an oil and water solution

I am wondering what would happen if I put a small (between $\mathrm{5mm}$ and $\mathrm{1\mu}$, density between $\mathrm{1}$ and $\mathrm{2\: g/mL}$) item with both oleophobic and hydrophobic ...
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40 views

Measuring the effect of increasing salinty on the concentration of Dissolved oxygen

I want to investigate the effect of increasing salinity on the concentration of dissolved oxygen, in a water sample being distilled water. Would that work? My concern is, that since its not a true ...
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0answers
248 views

Why does egg yolk turn white when washed with water?

I recently noticed that whenever I washed the egg yolk stuck on some utensils the water becomes milky white. It has to be the egg yolk that turns white and give off the white color to water right?
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69 views

Is there something which will block liquids but is dissolved by blood?

Is there a material which can be applied to a surface that will block liquids but is dissolved by blood? The idea is to use the liquid to close a circuit, but only if blood is present. I'm wondering ...
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40 views

Analytically combining Dynamic Equilibria that have a two way affect?

Lets say I want to model a water system as the following set of equilibria: $\ce{H2O <=> OH- + H3O+}$ | $\ce{A=[OH^{-}][H3O+]}$ $\ce{CO2 + H2O <=> H2CO3}$ | $\ce{B=\frac{[H2CO3]}{[CO2]}}$...
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Is it possible to raise pH in RO water without Na, Mg, K, Ca, S addition?

Maybe the question in the title is simple (=stupid) and the answer is 'simple No' but I have the urge to ask. Some background, I have an aquarium which I use RO water and I use some portions of $\ce{...
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38 views

Degree of Hardness Numerical

To remove the temporary hardness from $5\ \mathrm L$ of $\ce{H2O}$ $5.6\ \mathrm{mg}$ of lime is required. Calculate the degree of hardness due to $\ce{Ca(HCO3)2}$ present in water. My attempt: $$ \...
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Difference in properties of water as ligand vs 'in lattice'

I'm trying to understand the difference in properties between water in crystals in different positions in the lattice. In this wikipedia article It quotes: Both notations can be combined as for ...
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209 views

Electrolysis in water with baking soda

Many demonstrations of electrolysis show the use of baking soda and a 9 volt battery for electrolysis of water. As a science experiment, I tested different voltages by adding more batteries. In my ...
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100 views

What's the density of a frozen ethanol or ethanol solutions?

How can we know what's the density of ice (water), but there's no data on how much is the density of frozen ethanol? (as far as I know)
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109 views

What is the origin of the huge difference in the autoprotolysis constant of heavy water versus regular water?

Basically, the gist of this question is, why is the autoprotolysis constant of heavy water different from that of ordinary water? The autoprotolysis constant of heavy water at $\pu{25 °C}$ is $\pu{1....
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30 views

failed simple experiment with surfactant

I wanted to show my son the effect of a surfactant. So I filled two small glasses with tap-water, added a squirt of RinseAid to one and stirred. Then I sprinkled powdered flour on both. My ...
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54 views

Magnetic Water Softener

I've been asked to install some kind of technology to a building with 40 rooms to soften the water. Browsing through the product catalog I found this so called "Magnetic Water Softener", however ...
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75 views

Is it a coincidence that pKw = 14.00 at SATP?

High school chemistry student here. For our purposes in class for studying acids and bases, we are taught that $\text{p}K_\text{w}=14.00$, which is central for many of our calculations. I assume this ...
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246 views

How do water molecules overcome the van der waals distance and form hydrogen bonds?

I read in Voet & Voet that the hydrogen bonds are at least 0.5 angstrom shorter than the calculated van der waals distance. As I understand, van der waals distance is the distance of closest ...
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312 views

Does Ni(H2O)6 have Oh symmetry or Th?

I optimized a geometry of $\ce{Ni(H2O)6}$ using quantum chemistry and got a molecule which is symmetrical for the $\ce{Ni-O}$ distances as shown here: In the literature it says that this complex has ...
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707 views

Can water be included in an ICE table if it is not the solvent and is a product?

The question that I have is whether you will count water in a Fischer esterification equilibrium problem where the equation is carboxylic acid + ethanol --> ethyl acetate + Water We need to find the ...
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284 views

Does iron in water become visible when being heated?

I'm using ground water to provide my daily needs: Laundry, bath, toilet, ... I don't use it as drinking water, but I do cook with it. What I noticed is that when using the water cold it appears as ...
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269 views

How much water evaporates during a given time?

I read some questions such this for example and I asked me another question. Instead of only calculate how much time does it takes to have a cup of tea at room temperature, I'm asking how much time ...
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2k views

Heavy water dielectric constant

Why is heavy water less dielectric than normal water? Is it because of the fact that heavy water is more denser? I think it so because the dipole moment of heavy water is greater than normal water?
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What is the surfactant's role in the non-coalescence of water droplets?

I have recently seen many videos that talk about the noncoalescence of water droplets; however, I do not understand the purpose of adding surfactants into the water. From my knowledge (high school), ...