Questions tagged [equilibrium]
The state in which both reactants and products are present at concentrations which have no further tendency to change with time.
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Why are activities of solids and liquids taken to be unity?
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?
However, the treatment there is qualitative and I do not really ...
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Relation between chemical kinetics and chemical equilibrium
In my chemistry book, the law of chemical equilibrium is derived from the law of mass action:
For a reversible chemical reaction $$\ce{aA +bB\rightleftharpoons cC + dD}$$ where $a$, $b$, $c$ and $d$ ...
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Does the number of H+ ions in solution go up on dilution of a weak acid?
In my textbook, a footnote says:
In case of weak acids, on dilution the total number of $\ce{H^{+}}$ ions in solution increases because dissociation of the weak acid increases
This didn't make ...
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What is the Ka of OH- and Kb of H3O+?
What is the $K_\mathrm{a}$ of $\ce{OH^-}$ and $K_\mathrm{b}$ of $\ce{H_3O^+}$? Have these constants been determined?
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How can the equilibrium shift, while Kc remains constant?
Consider the following reversible reaction.
$$\ce{Cr2O7^2-(aq) + H2O(l) <=> 2 CrO4^2-(aq) + 2 H+(aq)}$$
What will happen to the position of equilibrium and the value of $K_c$ when more $\ce{H+}$ ...
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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
$$K_{\mathrm{a}}=\frac {\ce{[NH3]} \cdot \ce{[H3O+]}}{...
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Why does the equilibrium constant depend on the temperature but not on pressure and concentration?
According to my textbook (and intuitively) certain changes when the aforementioned 3 variables are altered occur in accordance with Le Chatelier's Principle. However, what I don't understand is what ...
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What are the units of Kc and Kp?
They are both equilibrium constants as far as I know.
Kc is in terms of molarity and Kp is in terms of pressure. Also both of them are ratios of respective quantities [ ratio of molarity(s) in Kc and ...
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Gibbs free energy-minimum or zero?
A reaction proceeds towards the direction of lesser Gibbs free energy (at constant $T$ (temperature) and $P$ (pressure)). So, we could say that Gibbs free energy at equilibrium is minimum.
On the ...
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How is volatility useful in the production of acids?
Sulfuric acid because of its low volatility can be used to manufacture more volatile acids from their corresponding salts.
How does volatility affect the production of acids? Isn't it that sulfuric ...
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What is active mass?
I'm aware of the fact that active mass is defined as the molarity of a substance, but my textbook states that
"Active masses are dimensionless quantities but for our purposes we generally take them ...
user33789
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What is the correct unit for the equilibrium constant?
I have the following equation
$$K_a = \dfrac{c\alpha^2}{1-\alpha},$$
with units $c= \pu{mol/cm^3}$ and $\alpha$ is the same. I'm not sure how to get the correct units for $K_a$. What I have come up ...
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Derivation of relationship between equilibrium constant and Gibbs free energy change
Why is $\Delta G=\Delta G^o+RT\ln Q?$
It feels like all online sources were written for introductory Chemistry students! Where do I find a rigorous proof of this identity? Greatly appreciate it!
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Find the pH of an amphiprotic salt dissolved in water at room temperature
Let's say I have a polyprotic acid $\ce{H2A}$ with the following properties:
$$
\begin{align}
\ce{H2A &<=> HA- + H+} & K_1 &= 1\cdot 10^{-1}\\
\ce{HA- &<=> A^2-+ H+} & ...
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Chemical Equilibrium - Why do changes in pressure cause a shift in the ratio of products and reactants?
I understand Le Chatelier's principle and how every change to an equilibrium system causes an opposing reaction from the system. I also understand how, when pressure is increased, the equilibrium ...
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