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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.

101 questions with no upvoted or accepted answers
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10
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0answers
135 views

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 ...
10
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1answer
257 views

What might serve as an initial starting photocatalyst for this large water-splitting solar simulator?

The Gizmodo article Insane Light System Blasts the Energy of 10,000 Suns and Phys.org's Let there be light: German scientists test 'artificial sun' both describe the large, powerful concentrated light ...
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1answer
98 views

Will the sulfur-iodine cycle and Haber Method work at lower pressures and temperatures?

I have a year-long research project next year in my senior year of high school, in which we have to make some product or prototype to solve some issue. My interest was in the Liquid Fluoride ...
6
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201 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 ...
6
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0answers
2k 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 ...
6
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501 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 ...
5
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0answers
81 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 ...
5
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0answers
102 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 ...
5
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148 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 $\ce{H+} \text{ and } \ce{OH}$ ...
5
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1answer
808 views

Is there a food-safe hydrophobic liquid with a substanially higher density 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 ...
4
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55 views

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 ...
4
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53 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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75 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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67 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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79 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. ...
4
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1k views

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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519 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 ...
3
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0answers
30 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 ...
3
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0answers
76 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 ...
3
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271 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 ...
3
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0answers
480 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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135 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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77 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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32 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 ...
2
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0answers
110 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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527 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 ...
2
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0answers
95 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 ...
2
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0answers
75 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, ...
2
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0answers
145 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 ...
2
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0answers
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 ...
2
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0answers
54 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 ...
2
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0answers
41 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 ...
2
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0answers
253 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?
2
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71 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 ...
2
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0answers
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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0answers
44 views

UK - Testing for Tap Water

Water is pooling in my garden next to my neighbour's fence. He has been harassing us in multiple ways for 8 years. It is the only place on my property where this is happening. It has never happened ...
1
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1answer
43 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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0answers
37 views

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 ...
1
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1answer
60 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 ...
1
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0answers
45 views

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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0answers
332 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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0answers
25 views

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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0answers
528 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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0answers
173 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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138 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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0answers
33 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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0answers
56 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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0answers
81 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 ...