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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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Solubility of CaCO3 in RO water [closed]

Is it possible to dissolve $\ce{CaCO3}$ in RO water of 5 PH? What is the amount per L that can be dissolved? Thanks
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1answer
19 views

Does TDS meters measure CO3/HCO3?

I am trying to add 2 g of KHCO3 to 20 litres of RO water (5.2 PH) which theoretically it will add K 10.32 ppm HCO3 16.1 ppm Will my TDS measure only the K (10-11 ppm) or it counts also HCO3 (26-...
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2answers
85 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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0answers
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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40 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{...
2
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1answer
138 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) ...
4
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1answer
47 views

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 ...
4
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0answers
34 views

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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0answers
10 views

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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0answers
116 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 ...
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0answers
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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1answer
107 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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24 views

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
194 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
28 views

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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2answers
219 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
47 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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28 views

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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0answers
20 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 ...
2
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1answer
30 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
61 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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1answer
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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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0answers
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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1answer
61 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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0answers
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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
137 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 ...
5
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1answer
173 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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2answers
391 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
30 views

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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0answers
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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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-...
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0answers
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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4answers
154 views

Where does the potential energy of capillary action come from?

Capillary action is when water pulls itself up a paper towel, glass tube or a tree. It is going up, which results in an increase in potential energy. According to the law of conversation of energy, ...
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1answer
684 views

I left a bottle of water in the fridge for the past three months. I took it out today. There was a block of ice in it. How?

How is this even possible? I know my fridge is not freezing items. The bottle was sitting at the back and I totally forgot about it. I went to empty it and heard a clank and noticed there was ice in ...
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1answer
78 views

Can running water carry an electrical current indefinitely, and for long distances?

Okay, not a scientist, but doing a writing project that requires a little knowledge. My question is: If there's a constant source generating enough energy into running water (like a stream, surrounded ...
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2answers
4k views

Why does ice crack when a drink is poured on it?

I think most people have experienced this, but while pouring a beverage over ice I noticed the ice cracked. Before After My initial thought was that because the beverage has an antifreeze property ...
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1answer
40 views

How to show a band structure for water?

This question is generated by my attempt to answer this one. I thought I could demonstrate that electronic conduction in water is possible because of the impact of an electric field on the band ...
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1answer
211 views

H2O and Le Châtelier’s principle [duplicate]

According to Le Châtelier’s principle, the adding of a reactant causes a shift in the direction of products, to minimize the modification. But what about $\ce{H2O}$? When can it be considered as a ...
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4answers
273 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
101 views

What would be different about a heavy-water ocean world?

The water on Earth is primarily made of $\ce{H2O}$. I'm wondering about the conditions in a hypothetical $\ce{D2O}$ ocean world. Would it be stable over geologic timescales (~$\pu{0.1–2 Ga}$)? What ...
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3answers
817 views

Properties of Water

Water is a substance characterised by properties such as high boiling point and its ability to act as a universal solvent. So why do we say that “the smallest unit of water is a water molecule”? ...
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2answers
217 views

What is the real pKa of water?

What is the $\text{p}K_\text{a}$ of water? A simple google search yields the value $15.74$, but this site and this paper say it's $14.0$. According to my understanding, the correct answer should be $...
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2answers
3k views

Would sodium explode in salt water?

I’ve seen the video etc of sodium being put into freshwater and the reaction of flames/small explosion but I wonder if the same reaction would occur if conducted in salt water such as the ocean.
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1answer
29 views

Is there any difference between thermal energy at room temperature in fluids(water) vs air?

Context of the question: I was reading on hydrogen bonds, specifically how close they are to the thermal energy of the fluids. So I googled the value of thermal energy at room temperature, which was $\...
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0answers
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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1answer
62 views

Urea + water yields … urea + water?

I added urea to water and, predictably, observed a temperature drop (10 C). I wanted to place the beaker under (reasonably) high vacuum (for a classroom) and recover the urea as a dry substance. ...
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0answers
10 views

Density change due to hydrogen bonding in water and other compounds [duplicate]

I know that the hydrogen bonding between the water molecules causes water to expand when frozen (compared to water at 4 degrees). Do other compounds that contains hydrogen such as hydrogen sulfide and ...
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0answers
221 views

Why does hydration enthalpy decreases instead of increasing down the group?

I have seen in my text book that for group 1 and 2 metals the hydration enthalpy decreases down the group.The reason I have found on the postWhich d-block cation has the maximum hydration enthalpy? is ...