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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White Spot Turning Red on Egg when Wet

NOTE: Not sure this is the right forum, but hope it is. I have a chicken egg with some white spots. See below and the white spot at the top. When making this egg wet with normal tap water, this spot ...
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What chemical changes happen in a factory? [closed]

I need help with that. I have to talk about chemical changes in factories on my chemistry class.
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4answers
84 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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48 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 ...
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What is deionized water used for in an industrial setting?

I've been working in a quality lab at a major PVC siding plant for the better part of a decade now, and I can't bring myself to ask what we use the deionized water from the cabinet for. It's in a ...
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23 views

sparkling whiteish water from kitchen tap [closed]

My shower drainage was clogged, so after trying mechanically I went to the shop for a liquid to unclog it (sorry im not an english speaker). This liquid contains 5 - 15% phosphoric acid and 85% ...
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35 views

To which extent is the function of an RO unit affected by inlet water type?

I want to purchase a Reverse osmosis water filter for my home but the issue is that the source of water supply is not always from a single source and hence parameters/properties of source water may ...
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1answer
44 views

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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23 views

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
30 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
39 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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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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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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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
81 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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1answer
88 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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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
37 views

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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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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2answers
157 views

Can caustic soda (sodium hydroxide) be used to dissolve urine odour?

I have an area of artificial grass at home in the back garden and during the summer months, the area emits a smell which I can only think is from the dog's urine when he pees all year long. The smell ...
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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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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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1answer
155 views

When it rains, it puddles. Spilled salt cycles between wet and dry with humidity. Is this akin to a phase change?

I have some spilled un-iodized table salt (NaCl). It is very humid where I live, and when it gets very humid for a few days, the salt absorbs so much water that it becomes a puddle of (probably) ...
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1answer
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What is the range of values of n in [Cu(NH3)4(H2O)n]SO4?

My textbook represents the copper ion as "tetraaminecopper(II) sulfate-1-water", so I assumed that this complex ion has only 1 water of crystallization. Then, in the Wikipedia article, they represent ...
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Why mixing water with ethanol produces heat energy? [closed]

Sorry if I'm asking something stupid but I'm trying to understand where this energy gets from. As far as I could find, it is not a reaction as both chemicals left unchanged, so it might have something ...
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DHA’s for tanning and water

I’m trying to make my own bath soak for fake tanning and have run into a road block with DHA’s as they (for lack of a better word) don’t agree with water! Is there a way I can fix this so that I can ...
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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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49 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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1answer
162 views

Would the change in enthalpy (ΔH) for the dissolution of urea in water be positive or negative?

To test the properties of a fertilizer, $15.0\ \mathrm g$ of urea, $\ce{NH2CONH2(s)}$, is dissolved in $150\ \mathrm{mL}$ of water in a simple calorimeter. A temperature change from $20.6\ \mathrm{^\...
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Why does energy need to be “compensated” in order for solvation to occur?

I am currently learning about the physical properties of alcohols. I understand that the main intermolecular forces between alcohols and water are hydrogen bonds. When these two are mixed, the ...
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1answer
201 views

Electrolysis of water: Which equations to use? (IB Chem)

There is a list of standard electrode potentials at 298 K from the p. 23 of IB Data Booklet 2016. Which of the following equations (forward/backward reactions), from the two possible ones involving ...
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1answer
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Carbonic acid, bicarbonate in water [closed]

When you add CO2 into water, carbonic acid is created. From carbonic acid (H2CO3), HCO3 + H is formed. When CO2, and H2CO3 leave the water, does HCO3 leave as well, often measure as kH, carbonate ...
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319 views

Cp vs Cv for liquid water @ < 4 °C

I'm looking at a textbook question (Engel & Reid, Thermodynamics, Statistical Thermodynamics & Kinetics, 4 ed, Q3.1) which states the following: The heat capacity $C_{\mathrm m,p}$ is less ...
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1answer
56 views

Why doesn't open-chain glucose react with water readily in aqueous solution?

Though the exact number given varies from 0.02% to 3%, it's well agreed that glucose spends a very small percentage of its time in aqueous solution as a linear aldehyde. Glucose's overwhelming ...
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water molecule orbitals in MO=LCAO theory

In the picture below I have evaluated the combinations of atomic orbitals which belong to the same symmetry specie using the standard method with the character table. Now I think that in order to ...
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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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1answer
39 views

What are we seeing in this AC salt-water copper-wire experiment?

There's a highly watched video on YouTube by "ElectroBoom" on the effects of passing AC (not DC) current through salt water. The water gets cloudy and at the end of the video we can see one of the ...
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1answer
65 views

Equilibrium constant of water

If $\ce{H2O}$ dissociates as follows: $$\ce{2H2O <=> H3O+ + OH-}$$ and not in this way: $$\ce{H2O <=> H+ + OH-}$$ why is the equilibrium constant: $$K_{eq}=\frac {\ce{[H+][OH-]}} {\ce{[H2O]...
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Determining the formula of tin(II) chloride hydrate [closed]

$\pu{1.20 g}$ of hydrated tin chloride decompose to form $\pu{1.01 g}$ of anhydrous tin chloride on heating. Calculate the value of $x$ given $$\ce{SnCl2.xH2O -> SnCl2 + x H2O}$$ I done it ...
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134 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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1answer
78 views

Miscibility of Hexane and Ethanol (Anhydrous vs 96%)

In my lab, I mixed 8:2 (mass:mass) of Hexane:Ethanol (Hexane: 0 ppm of water content, ...
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Scrubbing CO2 from atmospheric tank air supply

I am speccing a system for highly purified water which will be stored in an atmospheric tank. The tank comes with HEPA filters that will keep out things like dust, spores and bacteria, however, CO2 ...
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2answers
160 views

What is the best way to calculate the mass percentage of Calcium Carbonate from water?

Where I live it's believed that local tap water is really bad for drinking because of the amount of limestone. As a science experiment for school I wanted to approximately calculate the percentage of ...
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1answer
189 views

What is wrong with storing deionized water in glass containers?

I have heard that in general storing deionized water in glass bottles is ill advised and that it is better to use plastic. Additionally this is especially important for water used in ICP. I have ...
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393 views

What is a good source for large tables on the properties of water?

I'm currently doing an investigation for school on finding the Clausius-Clapeyron relation/gradient for boiling water and comparing it to the gradients along my line of best fit. It is given by the ...
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1answer
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Does mixing calcium dichloride and magnesium sulfate induce a reaction, and how does it affect the hygroscopy of the sample?

I have a problem with a sample made from $\ce{CaCl2*2H2O}$ and $\ce{MgSO4*7H2O}$ in about equal amounts. I took the two salts, pressed them together, and the result was a weird brine that was very wet ...
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1answer
32 views

Does oxyhydrogen require the presence of water to ignite?

I recently read a short story (fiction) where a major plot element was based on the expectation that a mixture of oxygen and hydrogen will not ignite unless some amount of water is present to get the ...
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1answer
44 views

What is a good resource for learning about the intermolecular bonding in water beyond high school? [closed]

I'm writing a paper for school on boiling water at various temperatures and pressures, but only noting cases wherein high temperatures were achieved without boiling under low pressure (metastable ...
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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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2answers
57 views

Precipitation of AgCl from the tap water solution of the group 2 chloride

I had this question about an experiment where the group 2 chloride was dissolved in distilled water and excess $\ce{AgNO3}$ was added to the solution to form $\ce{AgCl}$ precipitate. One of the sub-...