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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2
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1answer
94 views

How would you describe this?

This equation has been described as an equilibrium in an article, how would you explain it to someone with not a lot of understanding of it. The equation is: $\ce{CH3COOH <-> CH3COO- + H+}$ ...
1
vote
1answer
20 views

calculate the pressure at equilibrium

Given that $K=18$ for the equilibrium below, calculate the total pressure in a sealed vessel initially containing only $\ce{NH4I(s)}$, that reaches equilibrium. $$\ce{NH4I(s) ...
5
votes
0answers
46 views

A doubt on phase equilibrium?

Below is a transcript of this doubtful question: A weak monobasic organic acid HA issoluble in both solvents, water and $\ce{CHCl3}$. 500.0 cm$^{3}$ of a solution of $\ce{HA}$ is 0.057 mol ...
2
votes
2answers
75 views

About pH of an aqueous solution of SO2

How can I compare pH of an aqueous solution of $\ce{SO2}$ with that of pure water qualitatively? And I want to know what happen to the pH of an aqueous solution of $\ce{SO2}$ if I aerate it by ...
-2
votes
1answer
54 views

A doubt on equilibrium question?

To be honest this is a homework question. Below you can see a screenshot of it . Below you can see what I have tried , This is what I have got as the answer for Roman number one \begin{align}K_a ...
1
vote
1answer
35 views

When is equilibrium analysis appropriate?

What is a good rule of thumb to use to determine if equilibrium is the appropriate assumption? I assume it is mainly to do with the time scales of the problem, meaning if the reaction time scales are ...
5
votes
2answers
135 views

How will the equilibrium partial pressure of carbon dioxide be affected?

\begin{equation}\ce{CaCO3(s) -> CaO(s) + CO2(g)}\quad\Delta H^\circ = +556\ \mathrm{kJ/mol} \tag{endothermic}\end{equation} How will the equilibrium partial pressure of $\ce{CO2}$ be affected if ...
3
votes
1answer
32 views

Equilibrium constant in terms of mole fractions

$$\ce{CO + H2O <=> CO2 + H2}$$ A stoichiometric mixture of $\ce{CO(g)}$ and $\ce{H2O(g)}$ is allowed to reach equilibrium. $x$ is the mole fraction of $\ce{H2(g)}$ present. I am meant to ...
3
votes
1answer
50 views

Temperature dependence of equilibrium constant

On looking over the usefulness of quantity enthalpy change, I found that it can also be used to calculate temperature dependence of equilibrium constant, and I was wondering how could it be done, it ...
-1
votes
1answer
52 views

Final concentration … How to calculate it? [closed]

My question is here but i just want to find out how to go about it? If 50.0 mg of $\ce{CO3^2-}$ and 50.0 mg of $\ce{Ca^{2+}}$ are present in 1 liter of water, what will be the final ...
2
votes
2answers
44 views

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 ...
0
votes
0answers
21 views

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 ? ...
5
votes
1answer
287 views

How to find pH by mixing two solutions of different concentrations?

A mixture is made by combining 110 mL of 0.15 M $\ce{HCl}$ and 215 mL of 0.055 M $\ce{HI}$. What is the pH of the solution? $$\ce{HCl -> H+ + Cl-}$$ $$\ce{HI -> H+ + I-}$$ According to ...
4
votes
3answers
249 views

Which of the following compounds would result in the reaction being more active in the reverse direction?

$\ce{Fe(OH)2 (s) <=> Fe^{2+} + 2OH-}$ The reaction will be more active in the reverse direction if .......... is added a) $\ce{KOH}$ b) $\ce{Na2S}$ c) $\ce{Fe(OH)2}$ ...
2
votes
1answer
62 views

Chemical equilibrium and Le Chatelier's principle

Choose: $$\ce{Energy + 2KClO3 (s) <=> 2KCl(s) + 3O2 (g)}$$ The reaction will be more active in the reverse direction if: 1) $\ce{O_2}$ is added 2) more $\ce{KCl}$ salt is added. 3) More ...
-2
votes
1answer
70 views

How to calculate the mass of phosgene in the equilibrium mixture of carbon dioxide and dichloride? [closed]

I'm stuck on the last question of my homework and I really need some help! How much $\ce{COCl2}$ grams is in the equilibrium mixture? Consider the reaction: $$\ce{CO(g) + Cl2(g) <=> ...
2
votes
1answer
52 views

Approximating the concentration of ions when a salt dissociates

In my textbook written that: Given that $K_\mathrm{sp}(\ce{Ag2CrO4})=9.0\times 10^{-12}$, consider the solubility of $\ce{Ag2CrO4}$ in a $0.100\:\mathrm{M}$ solution of $\ce{AgNO3}$. Initial ...
2
votes
1answer
52 views

Is solubility in Qsp affected by coefficient?

Related to my previous question: Is solubility coefficient affected if ion data is given in Ksp? $200\,\mathrm{mL}$ solution of $0.02\,\mathrm{M}\,\ce{AgNO3}$ is added to $200\,\mathrm{mL}$ ...
1
vote
2answers
43 views

Keto Enol Equilibrium for Claisen Condensation Products

Do Claisen Condensation products prefer the di-keto form, or a keto/enol form due to increased conjugation and hydrogen bonding?
2
votes
1answer
38 views

Why does raising the temperature affect the mass of dissolved solute? [closed]

Consider a solution of $\ce{KOH}$ which is in equilibrium with undissolved $\ce{KOH}$ at $25\ \mathrm{^\circ C}$. After raising the temperature to $50\ \mathrm{^\circ C}$, the mass of undissolved ...
11
votes
1answer
146 views

How to calculate the pH of a saturated solution from its solubility constant Ksp and acidity constant Ka?

Given that $K_{\mathrm{sp}}(\ce{CaF2})=3.2\cdot 10^{-11}$, $K_{\mathrm{a}}(\ce{HF})=10^{-5}$, and $K_{\mathrm{w}}=10^{-14}$. Calculate $\mathrm{pH}$ of saturated $\ce{CaF2}$. Here is my ...
3
votes
1answer
39 views

Is solubility coefficient affected if ion data is given in Ksp?

Recently I've been looking at this website, which says: The $K_{\mathrm{sp}}$ of $\ce{Cr(OH)3}$ is $6.70 \times 10^{-31}$ Problem 1: What is the minimum $\mathrm{pH}$ at which $\ce{Cr(OH)3}$ ...
-2
votes
1answer
50 views

Need help with some equilibrium questions [closed]

I don't understand why the answer to this questions is A. I thought that the answer should be B since reaction 2 is just the reverse of reaction 1, and as such the position of products and reactants ...
2
votes
1answer
45 views

What is the effect of the temperature on the no of moles in an equilibrium system?

Here's something that makes me confuse. What will happen to the total no of moles in a system if the temp is raised. Will it increase? If so how is that possible.? Say we have an equlibrium, $$\ce{2P ...
1
vote
1answer
42 views

What is the value for the reverse reaction?

My question deals with the reaction $\ce{2NO(g) + O2(g) -> 2NO2(g)}$ with $K_c = 1752$. This is what I have so far; $K_c$= products over reactants, so is the reverse reaction reactants over ...
1
vote
1answer
39 views

Do all the precipitates undergo an equilibrium with its respective ions, why can't they dissociate fully?

I’m really confused about this. If we consider $\ce{Ca3(PO4)2}$, it can be seen it undergoes an equilibrium. But why it’s an equilibrium? This is the equilibrium it undergoes ...
6
votes
3answers
123 views

Quantum mechanical explanation for Le Chatelier's principle?

We know from basic chemistry that a reaction reaches equilibrium as described by Le Châtelier's principle. What's the quantum mechanical explanation to this principle? How a change in ...
4
votes
2answers
47 views

Equilibrium constant when adding more of a reactant

Suppose I have the reversible reaction: $$\ce{A +B⇌ C} $$ The reaction is at equilibrium with equilibrium constant $K$ I am told that if I increase the concentration of $\ce{B}$, the rate for the ...
2
votes
2answers
37 views

Are the following expressions for Kb (base dissociation constant) equivalent?

Given a weak base such as $\ce{C2H5NH2}$, I usually see the expression for $K_\text{b}$ as $K_\text{b} = \frac{[\ce{C2H5NH3+}][\ce{OH-}]}{[\ce{C2H5NH2}]}$. Are the expressions $K_\text{b} = ...
5
votes
4answers
109 views

What an aqueous solution really contains?

I want to know what an aqueous solution is. For example, let's consider a $1~\mathrm{M}$ aqueous solution of $\ce{MgCl2}$. Does it also contain $\ce{MgOH2}$? Though it is a simple question, I feel it ...
1
vote
1answer
71 views

Ksp calculation of Cr(OH)2

At $25~\mathrm{^\circ C}$, $10.24~\mathrm{mg}$ of $\ce{Cr(OH)2}$ are dissolved in enough water to make $125~\mathrm{mL}$ of solution. When equilibrium is established, the solution has a $\mathrm{pH}$ ...
-4
votes
1answer
42 views

Stability constant for metal ion complex using reduction potential [closed]

Determine the stability constant of the zinc tetramine complex from the equations: \begin{align} \ce{[Zn(NH3)4]^2+ + 2e &-> Zn + 4NH3} & E(\text{red}) &= -1.04~\mathrm{V}\\ ...
3
votes
2answers
33 views

Are carbocation intermediates in equilibrium?

So for the reaction of $\ce{H_2O}$ with an alkyl ethene, in the presence of $\ce{D^+}$ ions, forms two possible carbocations: $\ce{ R-CHD-CH2^+}$ and $\ce{R-CH^+-CH2D}$ The major product formed is ...
1
vote
1answer
86 views

Is ln(K2/K1) = (∆h°rxn/R)(1/T1 - 1/T2) even when ∆h°rxn varies strongly with temperature?

In all of my physical chemistry books I find the same expression for estimating the equilibrium constant of a reaction at a non-standard temperature. The derivation starts with $R \ln K_\text{eq} = ...
1
vote
2answers
72 views

Given a forward reaction with positive enthalpy, is its reverse reaction be endothermic or exothermic?

I'm pretty sure the sign changes. But, I want to be sure if it becomes endothermic or exothermic.
3
votes
1answer
74 views

le Chatelier's Principle

I am really confused about how reducing partial pressure of a gas by a certain percentage would impact the behavior of an equilibrium system. e.g $\ce{POCl3_{(g)} <=> POCl_{(g)} + Cl2_{(g)}}$ ...
2
votes
0answers
89 views

The distinction between dynamic & static equilibrium

How could we be sure that one certain reaction in equilibrium is dynamic? Since there would be no visible change in vessel, which property of the reaction would provide a proof besides color? Which ...
7
votes
4answers
83 views

Gibbs Free Energy of Solutes and Solutions

Using the equation $$\ce{CaSO4 (s) <=> Ca^2+ (aq) + SO4^2- (aq)},$$ and $\Delta H/\Delta S$ values, calculate $\Delta G$ at $50~^\circ\mathrm{C}$ when the solution is saturated with $\ce{Ca^2+}$ ...
-3
votes
1answer
48 views

How to calculate an equilibrium constant from concentrations and a reaction equation [closed]

2.50 mL of 0.0150 M A, 3.50 mL of 0.0250 M B, and 4.00 mL of distilled water were added to a 50-mL beaker. At equilibrium the concentration of C is 2.05*10^-3M at 25degrees celsius. Calculate Kc for ...
4
votes
1answer
74 views

Chemical equilibrium for simultaneous dissociation reactions

While calculating the adiabatic flame temperature for the following combustion reaction: $$\ce{\Phi\, C2H6 + $3.5$\,(O2 + $3.76$\,N2) -> $a$\,CO2 + $b$\,CO + $d$\,H2O + $e$\,H2 + $f$\,O2 + ...
2
votes
1answer
84 views

What is the reason for strong acids/bases dissociating in water?

I have read that the actual definition of a strong acid is one which will fully dissociate in water, so please do not turn the problem on its head when answering. It is also my understanding that ...
2
votes
1answer
33 views

Equilibrium Constant and Surface Area

At equilibrium, the rates of the forward and backward reaction become equal. In a reaction A(s) giving B(g) + C(g) Increasing the surface area of A increases the rate of the forward reaction, but the ...
8
votes
1answer
52 views

Writing Kp expressions?

How would you write the Kp expression for the reaction: $$\ce{4 Ag(s) + O2(g) \rightarrow 2 Ag2O(s)}$$ I know normally it would be products over reactants... but there is a solid on the product side ...
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vote
0answers
26 views

The concentration is unity! Why? [duplicate]

I want to know why concentration of solids and liquids are taken unity in expression of equilibrium constant( heterogenous equilibrium). It is usually mentioned that the density of solids and liquids( ...
3
votes
3answers
888 views

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 ...
2
votes
1answer
48 views

What's happening at the beginning of a weak acid titration?

At the beginning of a Weak Acid/Strong Base titration curve there is a sharp decrease in $[\ce{H+}]$ and a sharp increase in pH before the ratio between the weak acid and it's conjugate base becomes ...
2
votes
2answers
78 views

Spontaneous Reaction and Gibbs Free Energy

I know how to derive the expression for the equilibrium constant starting from $dG=0$, $$\ln(K)=-\frac{\Delta G ^o}{RT}$$ However, if we are not at equilibrium, $dG$ is not necessarily zero. In this ...
2
votes
1answer
185 views

How to find partial pressures from a given equilibrium constant Kp?

I had following question on my quiz and but I answer it wrong because I can't seem to solve it. It is related to finding equilibrium constant. Question: For the following reaction, at ...
2
votes
1answer
80 views

How many moles NH₄Cl must be added to NH₃ to create buffer with pH=9?

In my textbook there is the following problem: How many moles of $\ce{NH4Cl}$ must be added to $2.0~\mathrm{L}$ of $0.10~\mathrm{M}$ $\ce{NH3}$ to form a buffer with $pH=9$? Assume the addition ...
1
vote
0answers
80 views

Determining concentration of phosphate buffer from pH?

I bought a phosphate buffer from Sigma/Fluka (73212-1L) containing potassium dihydrogen phosphate ($\ce{KH_2PO_4}$) and disodium hydrogen phosphate ($\ce{Na_2HPO_4}$). It is at pH 8.0 but they do ...