Questions tagged [equilibrium]

The state in which both reactants and products are present at concentrations which have no further tendency to change with time.

Filter by
Sorted by
Tagged with
0
votes
0answers
44 views

Why is vapor pressure constant at boiling point?

At non-boiling point, I understand that when you add heat, temperature increases and also the amount of gas increases, so by using $PV=nRT$ at constant volume, the increase in $n$ and $T$ would ...
0
votes
1answer
56 views

Calculating numbers of moles at equilibrium given the volume of mixture and initial concentration of reactants [closed]

The equilibrium between three substances, A, B and C Is shown below. $$\ce{A(g) + B(g) <=> C(g)}$$ Initially there were $\pu{0.1 mol}$ of A and $\pu{0.2 mol}$ of B in the reaction mixture. A and ...
1
vote
2answers
54 views

Is is valid to compare reaction quotient to $K_p$ as well as $K_c$?

Can I use the reaction quotient compared to $K_p$ to answer the following question? The solid $\ce{XY}$ decomposes into gaseous $\ce{X}$ and $\ce{Y}$: $\ce{XY(s) <=> X(g) + Y(g)}$ with a $K_p = ...
-3
votes
0answers
13 views

ionic equlibrium [closed]

question is related to ionic euilibrium please answer option Q as soon as possible
-1
votes
2answers
38 views

What does enthalpy of formation at room temperature mean?

$\ce{AlCl3}$ has a standard enthalpy of formation some high negative value at $298\ \mathrm K$ $(-705.63\ \mathrm{J/mol})$. It means it's an exothermic reaction i.e will release heat. But my question ...
0
votes
1answer
37 views

Driving force in distillation

If the pressure is lowered in a distillation column, then the equilibrium curve will move further away from the diagonal (bulge out more) in an equilibrium diagram. This leads to a decrease in ideal ...
1
vote
1answer
43 views

What happens when the amount given doesn't allow for equilbrium to be achieved in a reaction?

The reaction $$\ce{A.3H2O(s) <=> A.H2O(s) + 2H2O (g)}$$ has a $K_p = \pu{400 mmHg2}$ One millimole each of $\ce{A.3H2O}$ and $\ce{A.H2O}$ are taken in a $\pu{1 liter}$ container at $\pu{300 K}$ ...
5
votes
1answer
78 views

Opposite effects of Le Chatelier's Principle

How does Le Chatelier's Principle deal with a change in reaction conditions which can simultaneously effect the equilibrium in opposite ways. For example, here's the equation for the conversion of $\...
1
vote
0answers
38 views

Calculating the number of volatile molecules in a container of known volume [closed]

Is it possible to calculate the number of volatile molecules (so only those in the gaseous phase) in a container of known volume, if the vapor pressure of the compound is known? So for example, if you ...
0
votes
2answers
53 views

How does current start to flow when galvanic cell is first connected?

Using the Daniell Cell as an example, where in the steady state we expect zinc to be oxidised and copper to be reduced spontaneously due to the overall reduction in Gibbs free energy, how does the ...
0
votes
0answers
20 views

Effect of adding pure solid/liquid in heterogenous equilibrium

QUESTION Consider the following reaction as an example: $$\ce{NaNO3(s) <=> NaNO2(s) + 1/2O2(g)}$$ Once this reaction has achieved equilibrium and then if we added pure $\ce{NaNO3}$ to this ...
-3
votes
0answers
55 views

Finding Ksp when HCl is titrated into a Ca(OH)2 solution [closed]

When $\pu{10.40 ml}$ of $\pu{0.1081 M}$ $\ce{HCl}$ is titrated into a $\pu{10 ml}$ of $\ce{Ca(OH)2}$ solution, what is the $K_\mathrm{sp}$ of resultant product? I understand that I need to follow ...
0
votes
1answer
46 views

Why isn't auto ionisation of water considered when we find the pH during salt hydrolysis?

$\ce{H+}$ concentration from the auto-ionisation of water is $10^{-7}$ If we have $\ce{HA}$ as weak acid and $\ce{BOH}$ as weak base having $\mathrm pK_\mathrm{a} = 3.2$ and $\mathrm pK_\mathrm{b} =3....
-1
votes
0answers
46 views

Effect of dilution on equilibrium confusion

An example provided in Pearson Chemistry Queensland 12 by Nick Holmes et al:1 $$\ce{Fe^{3+}(aq) + SCN^-(aq) ⇌ FeSCN^{2+}(aq)}$$ The figure above shows the effect of doubling the volume of the system ...
-2
votes
1answer
37 views

Comparison of the solubility of lead(II) iodide in water and in lead(II) nitrate solution [closed]

Solubility of $\ce{PbI2}$: Is $\ce{PbI2}$ more soluble in $\ce{H2O}$ or in an aqueous solution of Lead(II) nitrate? $K_\mathrm{sp} (\ce{PbI_{2}})=8.7\times 10^{-9}$ I'm not very good in Chemistry, I ...
0
votes
3answers
127 views

Why does the water dissociation constant Kw remains constant? [closed]

At $\pu{25 ^\circ C}$ at equilibrium the value of $K_\mathrm{w}$ is $\pu{1\times 10^{-14} M}$ and the concentration of $\ce{H+}$ and $\ce{OH-}$ is equal i.e. $\pu{1\times 10^{-7} M}$. Now if we add $\...
2
votes
1answer
46 views

Is this buffer possible?

Question Can a buffer solution be obtained by mixing- A) $\ce{NH4Cl}$ + $\ce{CH3COONa}$ B) $\ce{CH3COOH}$ + $\ce{NH4OH}$ My Thoughts I know that a buffer solution can be obtained if we mix a acid and ...
1
vote
1answer
36 views

What is an alternate way of preparing a sodium hydrogen phosphate/sodium dihydrogen phosphate buffer through titrating an acid with a strong base?

So my friend and I are stumped. This is in the context of achieving the sodium hydrogen phosphate/sodium dihydrogen phosphate buffer by titrating the acid with a strong base. My friend says the answer ...
4
votes
1answer
109 views

Common Ion Effect - Ionic Equilibrium

Question In which of the aqueous solutions of the following, dissociation of $\ce{NH4OH}$ will be minimum? A) $\ce{NaOH}$ B) $\ce{H2O}$ C) $\ce{NH4Cl}$ D) $\ce{NaCl}$ My Thoughts My book says that ...
1
vote
1answer
35 views

Temperature relation for isomerism reactions

When we have an isotherm isomerism reaction $\ce{A(g) -> A^*(g)}$ with $\ce{ΔH^0 = 0}$ is the ratio of preassures $\ce{P_A^* / P_A}$ independent from temperature?
2
votes
1answer
57 views

Why active mass of solids and pure liquids taken as unity

There is a similar question already asked here and answers provided say that activity of solid is taken as unity because their density dosn't changes... but I still have some doubts in it. Suppose we ...
-1
votes
2answers
62 views

why does the partial pressure not change? [closed]

Suppose I have the equilibrium in a closed container at constant temperature: $$\ce{2CaSO4(s) -> 2CaO(s) + 2SO2(g) + O2(g)}$$ If the volume of the container is halved, the reaction should move ...
0
votes
1answer
53 views

Thermodynamics of chemical reactions “at constant pressure”

Chemical reactions occur at constant temperature and pressure. Consider a gaseous, equilibrium reaction: $\ce{2NO2(g) <=> N2O4(g)}$. Most questions/textbooks formulate such questions by stating:...
0
votes
0answers
56 views

Effect of adding an acid or base to water with respect to concentration of ions

So I know that there's auto-ionization of water according to: $$\ce{2H2O <=> H3O+ +OH-} \tag{1}$$ If I have pure water where the concentrations of both $\ce{H3O+}$ and $\ce{OH-}$ is $10^{-7}$ ...
3
votes
2answers
69 views

Effect on mass when decreasing pressure in equilibrium reaction

For example, if we have the reaction: $$\ce{A + B <=> C}$$ And the volume is decreased, the pressure would increase. Hence, according to Le chatelier's principle, the system will partially ...
4
votes
1answer
85 views

How is the formula of mean activity coefficient derived?

The mean activity coefficient is defiend as follows: $$\gamma_\pm = (\gamma_+\gamma_-)^{1/2}.\tag{1}$$ If Debye-Hückel equation $$-\log\gamma_i = 0.5z_i^2\mu^{1/2}\tag{2}$$ is used, then the mean ...
0
votes
1answer
42 views

Equilibrium constant for heterogeneous equilibria having aqueous as well as gaseous reactants

Suppose we have a heterogenous equilibrium : $$\ce{A(aq) +B(aq) <=> C(g) +D(aq)}$$ Which equilibrium constant is used here? Both pressure and concentration terms are there. So, according to me, ...
2
votes
0answers
76 views

Equilibrium Constants for Diatomic Gases at High Temperatures

I'm new here and I haven't taken chemistry beyond high school, so please forgive the ignorance. I am reading a book about hypersonic aerodynamics, and I am trying to connect some chemistry knowledge ...
2
votes
0answers
31 views

Reducing pressure and calculation of concentrations at equilibrium

For the equilibrium $$\ce{PCl5(g) <=> PCl3(g) + Cl2(g)}$$ $$ K_c = \pu{4.16E-2 mol dm^{-3}}~\text{at}~\pu{250 °C}$$ $$[\ce{PCl3}] = [\ce{Cl2}] = \pu{0.204 mol dm^{-3}}$$ If the pressure of ...
0
votes
0answers
33 views

Why does Le Chatelier's principle work for temperature changes? [duplicate]

I do science tutoring. One of my students asked me why Le Chatelier's principle works, and I was able to explain it for concentration and pressure by referencing the law of mass action, but I could ...
-1
votes
1answer
91 views

An expression for equilibrium constant of isotope reaction

Consider the isotope exchange reaction: $$\ce{C ^{16}O + 1/2 ^{18}O {}^{18}O <=> C^{18}O + 1/2 ^{16}O^{16}O}$$ The equilibrium constant for the reaction is: $$K=\frac{\prod (a_i)^{n_i}_{products}...
2
votes
2answers
84 views

Dissolution of iron(III) hydroxide

Problem From the theoretical tour of the Mendeleev Olympiad in Chemistry: a) Calculate the minimal amount of sulfuric acid that should be diluted with water to yield $\pu{100 mL}$ of solution that ...
0
votes
0answers
31 views

Can there still exist equilibrium with a very high equilibrium constant?

Problem Consider the reaction translated by: $$\ce{2 CO(g) + O2(g) <=> 2 CO2(g)} \quad K_c = 2 \times 10^{22}~\text{at } \pu{1000 K}$$ The order of magnitude of the equilibrium constant, $K_c$,...
-1
votes
1answer
36 views

An equilibrium question involving mixing equal volumes of HCl and H2SO4

Question: Calculate the concentrations of H3O(+) and SO4(2-) in a solution prepared by mixing equal volumes of 0.2M HCl and 0.6M H2SO4. (Ka1 for H2SO4 is very large, and Ka2 for H2SO4 is 1.2E-2) Here ...
0
votes
1answer
51 views

Changing pressure on equilibrium

Recently I heard my teacher say that when increasing the total pressure of the system, the reaction which is "more dependent on collisions" is favoured. This seems to make sense, although I'...
1
vote
0answers
26 views

How can I analytically calculate the rate of thermal decomposition of calcium carbonate?

I am a first-time poster on Chemistry StackExchange, and not much of a chemist. I'm trying to determine the rate of thermal decomposition (in mol/s) of calcium carbonate ($\ce{CaCO3}$) at various ...
-1
votes
2answers
87 views

Which make HCO3- to show two pH values at two scenarios?

According to the below two titrations, Image Reference: https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_Chem1_(Lower)/13%3A_Acid-Base_Equilibria/13.05%3A_Acid%2F%2FBase_Titration If ...
1
vote
1answer
56 views

Why can’t I use solubility product for normally soluble compounds?

Solubility product only applies to sparing soluble ionic compounds (chemguide) I read this in a website. But I don’t see what this should be the case. Taking $\ce{NaCl}$ for example, there’s an ...
0
votes
3answers
91 views

Reversibiliy and equilibrium

My textbook states "A system is in thermodynamic equilibrium if it is in Thermal, Mechanical, and chemical equilibrium simultaneously". The Wikipedia article on "reversible processes&...
0
votes
1answer
64 views

Can the degree of dissociation of a weak acid be more than 1?

My common sense dictates that it can't be more than 1 because after all it is the number of moles dissociating per mole of a substance. But I was reading about Ostwald's law of dilution and came ...
2
votes
0answers
28 views

Why isn't the chemistry of a zinc-air battery (meaningfully) hindered by an activation energy barrier?

Virtually every source I've read pertaining to zinc-air batteries explain the chemistry of it either using these formulae or a simplified version of them: $$ \begin{align} &\text{Anode:} &\...
2
votes
0answers
58 views

Activity of a chemical species and compound

While reading a book on Instrumental analysis by Skoog, in appendix part they explain activity of a species. The relationship between activity of a species and it's molar concentration $[X]$ is given ...
4
votes
0answers
48 views

Is entropy maximum in equilibrium?

Usually, in the context of non-equilibrium thermodynamics, it is said that entropy achieves a maximum in equilibrium, so the Taylor series expansion of entropy around the equilibrium state as a ...
0
votes
4answers
91 views

How many grams of sodium phosphate must be added to precipitate as much of one ion as possible?

Problem text: Solid sodium phosphate is slowly added to $\pu{200 mL}$ of a solution containing $\pu{0.002 mol}$ of aluminum chloride and $\pu{0.001 mol}$ of calcium chloride (assuming no volume ...
1
vote
1answer
160 views

Why does a first order reaction only depend on the concentration of a single reactant?

I am new to kinetics so please explain it from basic, If there is a reaction - $$\ce{A + B + C -> D}$$ In first order reaction rate is given by- $\mathrm R = k[\mathrm A]$ or $\mathrm R = k[\...
4
votes
3answers
189 views

Is pK_{In} = pH at equivalence point still true for weak basic organic indicators?

I am reading Ostwald Theory of Titration which says that indicators are organic weak acids or bases. To prove the relation that $\mathrm{p}K_\mathrm{In} = \mathrm{pH}$, the textbook uses the following ...
0
votes
1answer
68 views

Latent Heat, Vapor pressure and Equilibrium [duplicate]

So after reading about this topic i wanted to share what i learned and i wanted you guys to tell me if what i am writting is correct: A pressure vessel has propane inside and it is pressurized. The ...
2
votes
0answers
35 views

Measuring vapour pressure in a closed system

My experiment requires the determination of vapour pressure from which I will calculate the number density (or number of moles of the molecule) later, for a closed system. Here's my setup : Liquid ...
2
votes
2answers
127 views

Van 't Hoff equation

In thermodynamics many definition has been made from partial derivatives at constant conditions for instance: Let $U$ be $U:f(S,V,m_𝑘)$ then: $$T = \left( \frac{\partial U}{\partial S} \right)_{V, m_{...
2
votes
1answer
44 views

Does the first step in electrophilic aromatic substitution follow equilibrium? If so, can equilibrium constant be calculated?

Using chlorine (a Lewis base) and ferric chloride (a Lewis base) as an example, the first step I saw in the textbook looks like this: The picture above depicts the Step 1 in the EAS mechanism using ...

1
2 3 4 5
27