Linked Questions

2
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0answers
46 views

Using equilibrium constant in gibbs equation [duplicate]

In my chemistry textbook, it is written that : Gibbs energy for a reaction in which all reactants and products are in standard state, $\Delta_\mathrm{r}G^\circ$ is related to the equilibrium ...
12
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2answers
5k views

Why does the equilibrium constant change on scaling the stoichiometric coefficients of a reaction?

I read in my textbook that if we multiply a chemical reaction by some factor(let's say $b$) its new equilibrium constant becomes $K^b$.But I don't understand why this happens.. What is the difference ...
18
votes
2answers
954 views

Which equilibrium constant is appropriate to use?

I have learnt that the standard free energy change is related to the equilibrium constant of a reaction by, $$\Delta G^\circ = -RT \ln K$$ Here, does $K$ refer to $K_p$ or $K_c$? Also, please give ...
10
votes
1answer
26k views

Derivation of van 't Hoff equation for temperature dependence of equilibrium constant

While I was reading about the usefulness of the quantity $\Delta H$, I found that it can be used to calculate the how the equilibrium constant varies with temperature. How can this be done? Does it ...
8
votes
1answer
11k views

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 ...
8
votes
2answers
843 views

Why proton concentration is divided by 10⁻⁷?

I am reviewing the book Biochemistry Concepts and Connections by Appling, Cahill, and Mathews and I cannot understand why they divide by the hydrogen concentration by $10^{-7}$. Why not just leave it ...
2
votes
1answer
22k views

Calculating Vapor Pressure from Delta G/ Kp

For the process, $\ce{CH3OH(l) -> CH3OH(g)}$ $\Delta G^\circ = 4.30\ \mathrm{kJ/mol}$ at 25 °C. What is the vapor pressure of $\ce{CH3OH(l)}$ at 25 °C in mmHg? (A) 0.176 mmHg (B) 14.0 mmHg ...
8
votes
2answers
2k views

What kind of equilibrium constant we use for Gibbs free energy and Van't Hoff equation?

We know that the Gibbs free energy is related to the equilibrium constant by the following equation: $$\Delta_\mathrm{r}G^\circ=-RT\ln K$$ We also know the Van't Hoff equation: $$\ln\left(\frac{K_2}{...
3
votes
2answers
188 views

Why is the equilibrium constant unitless?

I read that the equilibrium constant is unitless because the molar activities of each of the species are used in the equilibrium expression, not the actual concentrations themselves. I understand that....
2
votes
2answers
334 views

Gibbs free energy in standard state vs. equilibrium

I have a problem with the definition of the standard Gibbs energy and its connection to the equilibrium constants. I think, that I've basically understood what the different equation mean but there ...
1
vote
1answer
438 views

Proving RTln($a_i$) equal to non PV work done by system,where $a_i$ is activity

We know that chemical potential is defined as ${\mu}_i={\mu}_i^{standard}+RT\ln(a_i)$. Here $a_i$ is the activity of $i^\text{th}$ component of solution. In case of gases instead of $a_i$ it is $f_i$ (...
1
vote
2answers
148 views

Is the equilibrium constant in the expression based on pressure or concentration?

$$\Delta G^\circ=-RT\ln K$$ I have always assumed it to be $K_p$ because $\Delta G^\circ$ represents standard free energy change and the standard state for a gas is 1 bar. So I thought we must ...
1
vote
1answer
104 views

Why is the equilibrium constant given in litre per mole?

At $800\:\mathrm{K}$ a reaction mixture contained $0.5\:\mathrm{mol}$ of $\ce{SO2}$, $0.12\:\mathrm{mol}$ of $\ce{O2}$ and $5\:\mathrm{mol}$ of $\ce{SO3}$ at equilibrium. $K_\mathrm c$ for the ...
1
vote
1answer
238 views

Why isn't ΔG equal to zero for this equilibrium reaction?

In the reaction $\ce{E(g) <=> P(g)}$ at 25 °C, equilibrium is reached when the pressure of the product is 0.100 that of the reactant. What is $\Delta G$ in joules? Using $\Delta G = RT\ln K$, ...
1
vote
1answer
54 views

can i calculate equilibrium constant of this reaction?

Good day, i had organic chemistry labs. And we had this reaction: $$\ce{(CH3)3COH + HCl -> (CH3)3CCl + H2O}$$ My question is: how do i explain my yield of reaction is only 40%? My theory is: ...

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