All Questions
Tagged with equilibrium water
44
questions
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Resolve inconsistency regarding percentage of ionized water molecules in the auto-ionization of water
I am relearning some chemistry in order to understand pH for a particular application. My last encounter with the subject was in high school several decades ago. I have the following question:
I read (...
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2
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My textbook writes hydronium ion as [H(H2O)]+, is this correct? [closed]
[...] Thus, it bonds to the oxygen atom of a solvent water
molecule to give trigonal pyramidal hydronium ion, $\ce{H3O^+}$ $\ce{\{[H (H2O)]^+\}}$ (see box).
In this chapter we shall use $\ce{H^+(aq)}$ ...
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1
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Why is the ionic product of water also the equilibrium constant of dissociation of water?
This answer presents a derivation of the value of ionic product of water at $25^{\circ}\text{C}$.
The relation $K_\text{eq} = \operatorname{e}^{-\frac{\Delta_\text{r}G^{\circ}}{RT}}$ is used for the ...
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4
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How can the Kw of water be constant?
I know in neutral solution, $\ce{[H+]}= \ce{[OH-]}= \pu{1.0 x 10^-7}$.
However, let’s say I add an acid like HCl. This will increase $\ce{[H+]}$, therefore it’s no longer $\pu{1.0 x 10^-7}$, but is ...
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1
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Closed pressurized water vessel
Suppose we have a closed container not isolated from the external environment so that heat exchanges can occur on the lateral wall (mainly for convection). The water inside is pressurized by a gas (...
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1
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185
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How does an equilibrium move when increasing the concentration of water?
I have the following equilibrium given:
$$\ce{[Co(H2O)6]^2+(aq) + 4 Cl-(aq) <=> [CoCl4]^2-(aq) + 6 H2O(l)}$$
(I imagine the (l) for water is wrong, as the water is a part of the solution)
The $\...
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Why do we take active mass of water 1 but while calculating pKa of water as 55.345? [duplicate]
First, I should mention that the question was already asked here:Why is active mass of a pure solid or liquid always taken as unity?
But while calculating $\mathrm{p}K_\mathrm{a}$ of pure water we ...
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154
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Can water synthesis and decomposition be in a dynamic equilibrium?
When heated at extreme temperatures, water can spontaneously decompose.
According to Wikipedia (https://en.wikipedia.org/wiki/Water_splitting):
In thermolysis, water molecules split into their atomic ...
0
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Which reaction is happening in the preparation of sulfuric acid through contact process?
I've read that in the preparation of $\ce{H2SO4}$ through the Contact process, on the absortion tower, the gas $\ce{SO3}$ is getting in contact with $\ce{H2SO4} (l)$ , because adding $\ce{SO3}$ to $\...
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Can potassium carbonate be used to calibrate hygrometers?
Context:
In the process of trying to calibrate a number of hygrometers, with Sensirion MEMS electronic sensors, I came across the method of using wet salt: an airtight container will stabilize at a ...
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What is the difference between atom and nucleus? [closed]
Atomic nucleus-The atomic nucleus is the small dense region consisting of protons and neutrons at the center of an atom discovered in 1911 by EARNEST RUTHERFORD. Atoms are made up of a positively ...
-1
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1
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42
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Would adding a water soluble salt (e.g. NaCl) affect a water sensitive reaction?
Let's take for example a reaction that would benefit from having less water in it, ester formation from alcohol and acid. We know that the equilibrium can be shifted to the right (ester formation) if ...
6
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2
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Protons and osmotic potential
In a hypothetical enclosed membrane only permeable to water (including hydronium), where inside the pH is lower than the outside, would water move inside?
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487
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Equation of water at triple point
I was thinking about what exactly happens at the triple point of water, and what could be the effect of adding solutes/solvents. I feel we can represent the triple point using the following ...
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168
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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: $$K_{eq}=\frac {\ce{[H+][OH-]}} {\ce{[H2O]...
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H2O and Le Châtelier’s principle [duplicate]
According to Le Châtelier’s principle, the adding of a reactant causes a shift in the direction of products, to minimize the modification. But what about $\ce{H2O}$? When can it be considered as a ...
8
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1
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187
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What would be different about a heavy-water ocean world?
The water on Earth is primarily made of $\ce{H2O}$. I'm wondering about the conditions in a hypothetical $\ce{D2O}$ ocean world.
Would it be stable over geologic timescales (~$\pu{0.1–2 Ga}$)? What ...
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66
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Reason for formation of bubbles at boiling point [duplicate]
As I understand it, boiling takes place when the saturated vapour pressure equals to the atmospheric pressure.
But, why does the vapour pressure need to be equal to the atmospheric pressure for ...
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2
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Why does increasing the pressure cause ice to melt more?
This question was given under chemical equilibrium.
Why does increasing the pressure on this system cause ice to melt more?
$$\ce{H2O(s) <=> H2O(l)}$$
I'm pretty sure this has to be ...
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What does “to the left” mean?
However, the concentration of hydronium and hydroxide ions will be very, very small; in fact, the equilibrium that's established in solution lies so far to the left, that only 18 in 1010 molecules of ...
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479
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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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Why does pH decrease when diluting a base? [closed]
Take a strong base such a sodium hydroxide
Adding water will result in adding a hydroxide ions as well as hydronium ions to the solution
However if the pH decreases this means that the hydronium ion ...
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Why does hot water eventually turn cold, and why does cold water eventually turn hot? [closed]
I get cold water from my tap and put it in my water bottle. Over the day as I drink it, the water looses it coldness and slowly becomes warmer.
On the other hand, if I get hot water (maybe I'm sick ...
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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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190
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Why water won't dissociate more?
In a given sample of water some molecules of water dissociate to give hydronium and hydroxide ion. They say one in 10 million will be dissociated (approx.). What are the reasons behind this? Why water ...
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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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4
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789
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Relationship between the water ionization constant and ionic strength
I read in a textbook that
the water ionization constant ($K_\mathrm{w}$) increases as the ionic strength of the solution increases
and it confused me. If the ionic strength increased, then the ...
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868
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Ka relating to Dissociation of Weak acid and Water
I am studying $K_a$ currently and there is a passage in the book that doesn't appear to make sense.
It states that from the equation
$$\ce{HA <=> H+ + A-}$$
that $$K_a = \frac{[H^+][A^-]}{[...
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885
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What kind of 'product' is the 'product' in 'ionic product of water'?
My language has different words for product (=the result of a process) and product (=the sum of multiplied quantities), so I need to know the right meaning to choose the right word.
Which of the ...
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116
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The natural equilibrium of water
Why can the equilibrium reaction which exists in water be simply represented as
$$\ce{H2O <=> OH- + H+}$$
rather than
$$\ce{2 H2O <=> OH- + H3O+}$$
Doesn't this change both the ...
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391
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Is HCl(l) acidic?
If in a reaction mixture HCl is given in liquid phase, will it behave as an acid ?
I know that an aqueous solution of HCl is acidic but am confused about the liquid phase.
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Why is the ionic product for water $10^{-14}$? [closed]
Why is the reference value of $K_w=10^{-14}\ \mathrm{M}^2$, such that $[\ce{H+}]= 10^{-7}\ \mathrm{M}$ and $[\ce{OH^-}]= 10^{-7}\ \mathrm{M}$ for pure water at $20\ ^\circ \mathrm{C}$?
For example, ...
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Why is water not part of the equilibrium constant?
In the acid base reaction
$$\ce{NH4+ + H2O <-> NH3 + H3O+}$$
the acidity constant, which is a relation between concentrations is given by
$$K_{\mathrm{a}}=\frac {\ce{[NH3]} \cdot \ce{[H3O+]}}{...
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Can I freeze water at 100 °C if I add 28 grams NaCl in 100 grams water?
Can I freeze water at 100 °C if I add 28 grams NaCl in 100 grams water at 20 °C?
I found this diagram that says, if I have 28.05 wt% NaCl in water, then the equilibrium temperature between two phases ...
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370
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What is the difference between these equations for the Contact process?
Some webpages describe the contact process as this (I left out $\ce{SO2}$, $\ce{SO3}$ production):
$\ce{SO3 + H2SO4 -> H2S2O7}$
After this, it is controllable to add water to the oleum therefore ...
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How the heat a large amount of water that is safe to use?
I would like to know how heat up a large amount of water ( assumption : 100 liter ) that people could use to take their bath and also it would not be dangerous even if they accidentally ingested it ? ....
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2
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How concentrated can an acid be?
How concentrated can an acid be without it being supersaturated? Is there a certain limit to how concentrated an acid or base can be?
When I mean concentration, I mean molarity; so how concentrated ...
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3
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Is this the right conclusion for a thought experiment?
In this thought experiment, let’s consider the surrounding to be air that is composed of entirely water vapor (no other species like $\ce{O2}$ and $\ce{N2}$ are present). The surrounding is infinitely ...
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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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Ethanol and water hygroscopic equilibrium concentration
I am working with a company to help improve their reaction process where they use SDA 2B Alcohol (Karl Fischer titration has it at 99.66% EtOH, 0.3375% toluene). Specifically, I am attempting to ...
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Determining standard Gibbs free energy for water?
I am dealing with the dissociation of water into its components hydrogen and oxygen and I am trying to determine the standard Gibbs free energies of each component. My professor said if the substance ...
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Ionic Product of Water
Why is the ionic product for water ($K_\text{w}$) temperature dependent? The concentration of $\ce{H+}$ and $\ce{OH-}$ ions in pure water is $[\ce{H+}] = [\ce{OH-}] = 1.0\times 10^{-7}\ \mathrm{mol/l}$...
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Why does water dissociate to H3O+ and OH- rather than H+ and OH-?
Why does water dissociate to
$\ce{H3O+ + OH-}$
instead of $\ce{H+ + OH-}$?
This question came to surface when I was learning about acids and bases, and learned this definition:
$\mathrm{pH=}-\log_{10}[...
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Selectivity Coefficients of Ion Exchange Resins - Selectivity Reversal with TDS / Ionic Strength
I'm currently studying ion exchange resins and generally getting a bit stuck on some points of information which I do not fully understand / are not very well explained within the literature.
I ...
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