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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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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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What risks could arise from a piece of plastic falling into boiling water when cooking? [on hold]

What risks could arise from a piece of plastic falling into boiling water when cooking? My understanding is that the main risks could be due to leaching of additives in the plastic product rather ...
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1answer
38 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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9 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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18 views

Do reusable plastic water bottles break down [closed]

So many know that single use plastic water bottles break down with repeated use. Well the other day, I decided to buy a reusable water bottle. I am on a budget and picked up a Nike Hyperfuel 32oz. Its ...
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16 views

I need help to explain the reaction of a dissolvable magnesium alloy to the masses (Reaction within) [closed]

We use a Magnesium based metal alloy in an application where when the alloy is exposed to water with a high salinity (Chlorides) it dissolves. The below chemical reaction was provided and we would ...
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17 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 ...
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3answers
57 views

Isotopes of Elements

When we talk about the substance $\ce{H2O}$ with a molar mass of $\pu{18.0 g/mol}$, what hydrogen and oxygen isotopes are present in the $\ce{H2O}$ molecules? In other words, what isotopes do the ...
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1answer
45 views

Could Na+ ions in water used with a humidifier cause dust everywhere?

We have very dry air in our small family house. So we bought a humidifier ( https://www.klarstein.com/All-products/Monaco-Digital-Ultrasound-Humidifier-White.html ) But here comes the issue: the ...
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1answer
69 views

Which component in my tap water “scale” does not react with acid?

Where I live we have pretty hard tap water and so I'm used to scale build-up in kettles and on bathroom tiles, easily removed with acids (it's mostly calcium carbonate I guess). However it seems a ...
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2answers
597 views

Chemical composition of seawater

Is it true that the sea water is composed of about $86\%$ oxygen, $11\%$ hydrogen and $3\%$ of minerals? The chemical formula of water is $\ce{H2O}$ (two hydrogen and one oxgen) that shows that the ...
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1answer
72 views

Water as a “Harmful Acid”

Apologies for the question which is far below the brilliance of the minds on this page. I have an A-Level in Organic Chemistry but I'm tying myself in knots with this one. I'm a magician looking to ...
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0answers
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Experimental anomaly in boiling water with varying pressures and temperature

I have boiled ethanol, water, and bromine to determine there individual phase diagrams for vaporisation however in some cases (only with water) I managed to drop the pressure to 3-4 kPa while ...
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1answer
33 views

What is a simple formula to approximate the change in relative humidity as temperature rises/falls?

The moisture-carrying ability of air goes up as the temperature rises. So if I take a volume of air and heat it or cool it (allowing it to expand/contract so the pressure remains constant) how can I ...
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1answer
45 views

Oxygen Solubility in Water

This is probably really obvious, but I really don't understand. Why does oxygen dissolve in water when oxygen is a nonpolar molecule and water is a polar molecule? It's obvious that oxygen does ...
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1answer
29 views

Is the water in an aqueous solution undergoing a reaction considered part of the system or surroundings?

System: In chemistry, a system is a chemical reaction. A system operates within its surroundings. Energy can move between the two. Surroundings: The environment around a particular chemical reaction....
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1answer
39 views

Calculating the standard reduction potential for the oxidation of water

I was working with Latimer and Frost diagrams for oxygen when I came across what seems to me a contradiction. From the Latimer diagram for oxygen below, we know the standard reduction potential for ...
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0answers
27 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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0answers
36 views

How do acids disassociate? [duplicate]

When recently learning about acids and bases, I realized that I had perhaps not understood how it is that acids disassociate. I had always thought the proccess was like an ionic salt, where the water ...
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1answer
29 views

Does coffee have the ability to dissolve less sugar into it than water?

Like water can absorb such and such an amount of sugar, can coffee absorb less as it already has coffee in it.
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0answers
20 views

why water is colour less?

I see pounds, rivers and sea the water colour is blue but it is the reflection of sky the water has no colour. So my question is why water has no colour? why water is colourless?
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1answer
68 views

Why does humidifier put measurable PM2.5 in the air?

(I know little science so please help me if I'm in the wrong place or if my question needs editing. I could use help with tagging, for example.) I use two devices that measure PM2.5: Kaiterra ...
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1answer
43 views

Turning hot water to cold water [closed]

Is there a way to turn hot water instantly to cold water? Is there some sort of chemical reaction or element that allows this process to happen?
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1answer
18 views

Would atomic oxygen and atomic hydrogen result in O2 and H2 only, or some H2O too? [closed]

Let's assume we have atomic oxygen and atomic hydrogen in a closed chamber, the temperature and pressure of which we're able to monitor (and control). Number of hydrogen atoms are twice that of oxygen....
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2answers
26 views

Converting Chlorine Dioxide concentration to Chlorine

Looking for a little guidance. I have been given some water quality data as part of a project. Specifically I'm interested in the concentration of Chlorine in river water. The analysis results ...
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1answer
69 views

What component(s) of instant coffee make it deliquescent?

If I put small, separate piles of instant black coffee powder, sugar, powdered creamer, and even something very ionic like table salt out in humid air and come back in a few days, only the instant ...
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1answer
37 views

Acids using different solvents [closed]

Many polar protic solvents exist and ionic compounds are able to dissolve inside these substances for the same reason as water. So, theoretically, if a substance were to steal a $H^+$ ion from a polar ...
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1answer
77 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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1answer
45 views

Is the relative humidity of pure water vapour 100%?

If there is pure water vapour in the gas phase, can the partial pressure be taken to be equal to the vapour pressure of water at that particular temperature? edit: How is relative humidity calculated ...
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1answer
86 views

Diluting methanol in water: is it exothermic?

Can someone explain in simple terms why does temperature increase when mixing water with methanol? I do not have a strong background in chemistry, but I usually have to mix both liquids (sometimes ...
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1answer
125 views

Hygroscopic Substances and Drying Agents

My book says: Most of the hygroscopic substances are drying agents Based on what I read on several websites, I think dehydrating agents also act as drying agents. If so, all dehydrating agents ...
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1answer
22 views

Mechanism of Water Potential

The idea of water potential still confuses me. I understand the general idea: water moves from an area of higher water potential to an area of lower water potential. However, I still do not understand ...
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1answer
55 views

Understanding water models?

I generally work on fluid flow, so some basic concepts in chemistry are new to me. Work I'm doing requires use of molecular dynamics (MD) to do classical potential simulations of water–NaCl systems ...
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1answer
30 views

Which chemical could be used to decrease water boiling point to a minimum possible level without heating it [closed]

I aim to decrease boiling point of water that will be used to generate steam. I wonder maybe there is an opportunity to add a substance that will help to decrease boiling point of water without ...
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1answer
135 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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0answers
56 views

Reason for formation of bubbles at boiling point [duplicate]

As I understand it, boiling takes place when the saturated vapour pressure equals to the atmospheric pressure. But, why does the vapour pressure need to be equal to the atmospheric pressure for ...
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1answer
28 views

Will a container made of ice hold an alcoholic beverage that is below freezing in an environment that is also below freezing? [closed]

This very specific question that came after saw I a travel episode where they served alcoholic beverages in ice glasses in an ice bar. I wondered if the drink contents would stay in the glass (of ice) ...
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1answer
23 views

Removing water/moisture from car exhaust [closed]

I know that car exhaust is almost entirely nitrogen, water and carbon dioxide. How would I go about removing the water? Would I have to condense it off? Any devices already exist for doing so?
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1answer
846 views

Is there a compound that contains water as a subcomponent? [closed]

Is there a molecule that contains water chemically bonded to another molecule/element? Could someone provide an example or two?
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0answers
27 views

What happen if i keep etched silicon underwater?

I am trying to remove oxide of silicon by using etching solution. After etching, usually silicon turn shiny. But just out of curiosity i let it soak in water overnight, the surface of silicon is a bit ...
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1answer
581 views

Why is ammonia less acidic than terminal alkynes?

Here's a picture from Organic Chemistry by Solomons, Fryhle & Snyder : Why is it that ammonia is less acidic than terminal alkynes even though water, and even alcohols, are more acidic than them?...
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0answers
90 views

How to measure pH of deionized water

reverse osmosis deionized water (RODI) is used to rinse acid off silicon after it undergoes silicon etching. Sample of water is taken and measured by using pH meter. However, pH meter takes a 1-2 ...
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2answers
965 views

Why is creating water exothermic?

I have to calculate the bond dissociation energy of steam. I'm a total noob, so don't go too hard on me. (I'm translating the exercise by myself, sorry if there is a mistake.) Calculate the bond ...
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0answers
86 views

Why does IPA turn cloudy when added to water?

When I pour isopropyl alcohol into water (tap water not distilled water), it turns cloudy. I’ve heard that alcohol is miscible with water (the the liquids should not give a precipitate) . Also, what ...
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2answers
300 views

The effect of pH and solubility on coagulation in water treatment

In water treatment, a specific pH range must be met in order for the process of coagulation to occur properly. Sources have stated this is due to the pH affecting the solubility of the coagulant, but ...
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1answer
66 views

What is the solublity of water in liquid carbon dioxide at low temperature?

The solubility of water in liquid carbon dioxide has been investigated by Hosmer W. Stone in 1943 from -29 to about 22 °C. Is there any research done on the solubility of water in liquid $\ce{CO2}$ ...
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1answer
65 views

Can we manipulate the rate of water's autoionization?

I just got introduced to this concept and these thoughts came into my mind. Is there a way to increase the equilibrium constant of the autoionization of water?
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1answer
245 views

Is there a substance that hardens in water? [closed]

Im trying to invent a product that starts as a liquid but when exposed to water it hardens. Is there any chemicals that can cause this reaction??
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4answers
370 views

Why does the Leidenfrost effect (seemingly) not apply to the case of molten NaCl when it is poured into water?

On pouring molten sodium chloride into water you can see that when molten $\ce{NaCl}$ (table salt, i.e. sodium chloride) is poured into water ($\ce{H2O}$), the Leidenfrost effect appears to be ...
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1answer
58 views

How does the water pollutant sodium nitrate affect the concentrations of other ions in tap (dam) water? [closed]

Context In my assignment I've been given two water samples from the hinze dam. The first sample has been untouched, however the second has been contaminated with an unknown ionic compound. To ...