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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-4
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0answers
39 views

what is the equilibrium concentration of A? [on hold]

Solutions of A and B are mixed and brought to equilibrium. The starting concentrations of A and B are 0.80 mol/L, each. C and D are produced according to the following equation. $$\ce{A(aq) + ...
-2
votes
1answer
59 views

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

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) <=> ...
1
vote
1answer
34 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
36 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
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2answers
40 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
27 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 ...
8
votes
0answers
97 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
36 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
45 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
31 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
31 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
38 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 ...
4
votes
1answer
41 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 ...
3
votes
1answer
29 views

equilibrium constant when adding more of a reactant

Suppose I have the reversible reaction: $$A+B⇌ C $$ The reaction is at equilibrium with equilibrium constat $K$ I am told that if I increase the concentration of $B$, the rate for the forwards ...
2
votes
2answers
35 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
93 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
65 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
35 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
31 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
65 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
58 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
0answers
43 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
42 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
73 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
43 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
63 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
62 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
25 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
49 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 ...
1
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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
870 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
40 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
1answer
51 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
108 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
72 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
62 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 ...
0
votes
1answer
37 views

Ionic equilibrium equation [closed]

What form is the ionic equalibrium equation? I have problem asking for it, but I'be done so many different equalibrium equations that I'm starting to get mixed up on which one is called what... Which ...
1
vote
1answer
34 views

Partial pressure and chemical equilibirum

Suppose I am given following reaction in vessel $$\ce{NH4HS_(s) <=> NH3(g) + H2S(g)} $$ $P_{\ce{NH3}}=P_{\ce{H2S}}=1\,\mathrm{atm}$ at Equilibrium , If volume is doubled at this instant then ...
4
votes
1answer
20 views

What are the minimum required given sets of information to complete an ICE chart for an equilibrium reaction?

I'm considering creating a program that automatically completes an ICE chart/table when the minimum given information is provided. The reason I'm posting my question here is because I need to know the ...
0
votes
1answer
150 views

Finding new pH after NaOH added to buffer soln given original pH and concentrations of both components

I have a buffer containing 0.2000 M of the acid HA, and 0.1500 M of it's conjugate base A-, with a pH of 3.35. I need to find the pH after 0.0015 mol of NaOH is added to 0.5000 L of the solution. I ...
1
vote
1answer
225 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 ...
2
votes
0answers
43 views

Hemoglobin equilibrium - effect of increased carbon dioxide and lactic acid

The binding of oxygen by haemoglobin giving oxy-haemoglobin is partially regulated by the concentration of $\ce{H3O+}$ and dissolved in $\ce{CO2}$ in blood $$\ce{HbO2 + H3O+ +CO2<=>H+.Hb.CO2 + ...
6
votes
2answers
233 views

Peracetic acid stability

I've been trying to find out as much as I can about peracetic acid, especially regarding its use as a sanitizer. In the Wikipedia entry it notes that "[p]eracetic acid is always sold in solution ...
0
votes
0answers
28 views

Meaning of equilibrium in “Vapour in equilibrium with liquid”?

In my physical chemistry book it says "Consider a liquid sample of a pure substance in a closed vessel. The pressure of a vapour in equilibrium with the liquid is called the vapour pressure of ...
2
votes
1answer
39 views

What happens if I have an acid/base equillibrium and remove hydronium ions until there is 50/50 of acid and conjugate base?

Suppose I had an acid HA, and it reaches equilibrium in water. Then I remove the hydronium ions. I don't know how I would do this, maybe adding some hydroxide ions. My question is can I do this and ...
1
vote
0answers
51 views

Why is the vertical part of a titration curve longer for a strong acid by a strong base than for a weak?

As the title says, I would like to understand chemically why this occurs. My theory behind it is that in the former case both are completely dissociated, and so at the equivalence point (and ...
1
vote
0answers
20 views

How does adding Argon to this reaction affect the number of moles of each reactant? [duplicate]

We have this reaction: At equilibrium, we have 5.3 moles of $\ce{H2}$ and 5.4 moles of $\ce{HI}$. At some later time, 1.7 moles of Argon (the question states that this is an inertial gas and does ...
1
vote
1answer
63 views

Concentration of expanding gases

At $t = 0$ we have 10 moles of $\ce{NO2}$ and 10 moles of $\ce{N2O4}$ satisfying this reaction in a 0.75 liter tank (the barrier is closed at this time): $$\ce{N2O4 <=> 2NO2}$$ The system is ...
3
votes
1answer
54 views

How to predict the colour of a pH indicator using Le Chatelier's principle

Hi, The question I have is above. Could someone explain why the answer is A? Thankyou, this is greatly appreciated (this is in preparation for an exam, it is not cheating) What I think so far: -Does ...
2
votes
2answers
43 views

Help me understand the correlation between the equilibrium constant and delta G

I understand this up until the last two steps. How does $\text{ln}(K_{eq})$ become $2,303\text{log}(K_{eq})$ and how does $-RT*2,303$ become $-1,42$?