# Questions tagged [equilibrium]

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

1,181 questions
Filter by
Sorted by
Tagged with
432 views

### Can an iodine clock reaction work without using a strong acid?

I'm going to do an iodine clock reaction for a project and we had to submit the materials and safety sheets for the experiment a while ago. I thought I could do one by using hydrogen peroxide, sodium ...
521 views

### What is exactly meant by position of equilibrium? [duplicate]

I'm confused with the terms "position of equilibrium" and "equilibrium shifting towards left/right". I do have a vague picture that if a reaction shifts to the right, for example, it basically means ...
62 views

### Determining mole fraction of carbon dioxide knowing Kp only

I've been assigned the following problem at school: Given the following reaction: $$\ce{C (s) + CO2 (g) <=> 2 CO (g)}$$ Find the mole fraction of $\ce{CO2}$ provided that, in ...
306 views

374 views

### Changes in pressure for an equilibrium reaction containing a solid/liquid on one side only

For a reaction where there is only one solid/liquid present, but gases present as both reactants and products (are there any examples of this type of reaction?): $$\ce{A(s) + B(g) <=> C(g)},$$ ...
3k views

### 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 ...
109 views

### Why does ligand substitution occur when OH- is a better ligand than NH3?

$$\ce{[Cr(H2O)3(OH)3](s) + 6NH3 -> [Cr(NH3)6]^3+ + 3H2O + 3OH-}$$ When excess $\ce{NH3}$ is added to triaquatrihydroxychromium(III), why does ligand substitution occur when $\ce{OH-}$ is a better ...
127 views

241 views

### Doesn't Ostwald's law of dilution contradict Le Chatelier's principle?

By Le Chatelier's principle, increasing the concentration of a weak electrolyte brings out more ions. By Ostwald's dilution law, increasing the concentration of a weak electrolyte brings out less ...
186 views

### What's the difference between “extent of reaction” and “position of equilibrium”?

My chemistry textbook defines the terms in question as follows: Extent of reaction: the relative amounts of products compared with reactants. The extent of reaction is indicated by the value of the ...
188 views

### How to find equilibrium constant in reactions which have a limiting reagent?

If in the following reaction $$\ce{H2 + I2 <=> 2HI}$$ the initial concentrations of $\ce{H2}$ and $\ce{I2}$ are $\pu{1 M}$ and $\pu{5 M}$, respectively, and at equilibrium $x$ moles of ...
108 views

### pKa Conceptual Questions [closed]

If anyone could clear up some of this conceptual confusion, that would be much appreciated. Is $\mathrm pK_\mathrm a$ an intrinsic property of a molecule? Or extrinsic? A property is extrinsic if it ...
69 views

### Does concentration or pKa define acid strength?

For example, is 3M HCl a stronger acid than 1M HCl? I would reason that the concentration of an acid/base does not influence its strength. Strength is determined by the pKa, and, as per Le Chatelier'...
33 views

### Effect of increasing product concentration on time of completion of reaction

This was the question asked in our chemistry exam: In the experiment of determination of equilibrium constant of esterification of ethanol, if , instead of using clean dry bottle, if a bottle already ...
48 views

### Why does a Lower Concentration of SO2 call for an increase of equipment dimensions in a Contact Process Plant?

I'm working on a presentation based on an article about the Contact Process (production of sulfuric acid), and it says that using a low concentration of SO2 at the entrance of the converter (in which ...
136 views

### Manganese (II) oxidation by air

I am studying the reaction of dissolved dioxygen with manganese(II) hydroxide for the Winkler method: 2Mn(OH)2(s)+O2(aq)⟶2MnO2(s)+2H2O(l) The ...
139 views

### Polyprotic acid - How does one calculate the CONCENTRATIONS of ALL species present in a solution when you start with 0.3M NaH2PO4? [duplicate]

Can anyone give me a push in the right direction, how do I calculate the concentration of all species present in a solution with 0.3M NaH2PO4. So the concentration of H3PO4, H2PO4 -, HPO4 2-, PO4 3- ...
2k views

### How to derive the relation between gibbs energy and equilibrium constant?

I want to understand the derivation between gibbs energy and equillibrium constant $$\Delta G=\Delta G^o+RT\ln Q?$$ I have seen a similar post on CSE Derivation of relationship between equilibrium ...
57 views

### Chemical Equilibrium in case of copper(II) ions [closed]

$\pu{Cu^{2+}}$ ions react with $\pu{Fe^{2+}}$ ions according to the following reaction: $$\ce{Cu^+2 + 2Fe^2+ <=> Cu + 2Fe^3+}$$ At equilibrium, the concentration of $\pu{Cu^{2+}}$ ions is ...
here is an interesting question about the chemical equilibrium and Le Chatelier's principle. the following pressure show the partial that produced in the equilibrium reaction at time (t1 and t2) $$\... 1answer 1k views ### In a saturated solution, why is there ongoing dissolution and crystallisation? I was studying equilibrium, and had this question.. In a saturated solution with sugar dissolved, why is there a constant process of dissolving and crystallising? What I mean by this is, why don't ... 1answer 926 views ### What is the pH of a solution made by mixing 10.00 mL of 0.10 M acetic acid with 10.00 mL of 0.10 M KOH? What is the pH of a solution made by mixing 10.00 mL of 0.10 M acetic acid with 10.00 mL of 0.10 M KOH? The K_a =1.8 × 10^{-5} for \ce{CH_3CO_2H}. Assume that the volumes of the solutions are ... 1answer 144 views ### Equation for the equilibrium constant for the hydration of carbonyls using UV spectroscopy I was looking through the literature when I found this source: https://pubs.rsc.org/En/content/articlepdf/1967/tf/tf9676302131 Which states that the equilibrium constant Khyd is: Khyd = \frac{[... 3answers 2k views ### molar solubility of CaF2 at pH3 given molar solubility at pH7 and pKa of HF Here was my attempt #1 at a solution. K_{sp}=[Ca^{2+}][F^-]^2 Using the information at pH=7, I estimated that K_{sp}\approx3.7\cdot10^{-11}, which means that barely any HF formed. I assumed ... 1answer 219 views ### How can I find the equilibrium constant Kp without temperature? The question I'm looking at is I found that that Kc = 139M^-1, but how can I determine Kp? There is no temperature given, but I was told that it is still possible to calculate. 1answer 514 views ### Calculating molar solubility of calcium hydroxide from solubility product On the Wikipedia page for calcium hydroxide, the stated solubility product for \ce{Ca(OH)2} is K_\text{sp} = \pu{5.5 * 10^{-6} M^3}. It doesn't stipulate the temperature, but I have a chemistry ... 1answer 54 views ### Solving chemical equilibrium equation by hand [closed] I was trying to solve question 22 above. I obtained the equation:$$50=\dfrac{4\alpha^2}{(1-\alpha)(2-\alpha)}$$Now, the resulting quadratic is too much of a pain to solve. How would one use ... 2answers 58 views ### Is iron(III)nitrate changed and if so how? We have the solution: \ce{Fe^3+(aq) + SCN-(aq) <=>Fe(SCN)^2+} When we add more \ce {SCN-} to the solution above, the solution produces more product. My question is, how does it affect \... 1answer 273 views ### Why does a catalyst increase the forward and reverse reactions equally With reference to the picture below, how is it that when there is a lower activation energy (due to the alternate reaction pathway provided by the catalyst) that the catalyst will increase the forward ... 1answer 509 views ### Why are solids and liquids ignored in the equilibrium constant? If a reaction is taking place and is going towards equilibrium, wouldn’t the reactant be consumed to form products and vice versa? If this reactant/product is a solid or liquid, wouldn’t the number of ... 1answer 1k views ### How does Borax Solution act as a buffer? [closed] What type of buffer is it? If it's a Weak Acid-Conjugate Base type of buffer, what is the weak acid and conjugate base? 1answer 33 views ### Equilibrium expression for dissolution of carbon dioxide I was asked to give the equilibrium expression for:$$\ce{CO2(aq) + H2O(l) <=> H2CO3(aq)}$$As water is a liquid and a solvent here, it shouldn't be included in the expression, hence I wrote: ... 0answers 142 views ### Color change of aqueous ferric salt when reacted with phosphate I have a question about an equilibrium system:$$\ce{Fe^3+ (aq) + SCN-(aq) <=> [Fe(SCN)]^2+ (aq)}\\ \text{(yellow)} \quad \text{(colorless)}\quad \qquad\text{(red)}\qquad\quad$$The question ... 1answer 61 views ### What is the meaning of K in the thermodynamic equation for equilibrium constant? I just studied the formula for equilibrium constant in thermodynamics. But when an equilibrium is established \Delta G is always 0 as told by my teacher. Then k has to be always 1 whenever an ... 1answer 1k views ### How is silver chloride more soluble in brine than water? I heard that: Silver chloride is more soluble in very concentrated NaCl solution (brine) than in pure water. Is it true? I mean won't the common ion effect operate? Or may be this is due to some ... 1answer 28 views ### Finding the error in attempting the equilibrium question through isotherm equations Consider the partial decomposition of A as:$$\ce{2A(g) <=> 2B(g) + C(g)}$$At equilibrium \pu{700 ml} of gaseous mixture contains \pu{100 ml} of gas C at \pu{10 atm} and \pu{... 1answer 98 views ### Why is the equilibrium constant unaffected by a change of the initial concentration? In my class, it was taught that the equilibrium constant does not vary with the intial concentration of the reactants? Why is it so? 2answers 93 views ### Why is the concentration of protons equal to the concentration of a strong acid? First, I know that strong acids are assumed to dissociate completely in water, so that the concentration of \ce{H+} which they provide equals their concentration. What I am asking for is not the ... 1answer 64 views ### Buffer made of salts of polyprotic acid: reactions I was trying to make a buffer with \ce{K2HPO4} to use it in a bacterial culture. If I use \ce{K2HPO4} I think I have to add \ce{KH2PO4}. I am trying to think it writing the equations of the ... 4answers 2k views ### Titration of Na2CO3 against HCl \pu{25 mL} of \pu{0.125 M} \ce{Na2CO3} is titrated with \pu{0.100 M} \ce{HCl}. Given that K_\mathrm{a1} = 4.3\times 10^{-7} and K_\mathrm{a2} = 4.8\times10^{-11} for the diprotic acid \... 0answers 319 views ### Difference between Henry constant and equilibrium constant According to wikipedia, Henry constants define the ratio between the aqueous and gas fraction of a chemical species at equilibrium. Lets consider Henry constants H in atm.L.mol-1 such that [C]_{g} = ... 0answers 161 views ### How to without calculations understand the liquid-liquid extraction efficiency? I'm asking myself this question for a very long time and I haven't found a simple an good explanation yet for the fact that it's better (if you want to clean them) to wash your hands two times with ... 1answer 45 views ### Rate of a reaction [duplicate] We know that the rate of a reaction \ce{aA + bB -> cC + dD}, the rate of the forward reaction is given by r_\mathrm f = k_\mathrm f[\ce A]^p[\ce B]^q where  a\neq p and  b\neq q according ... 1answer 166 views ### Why don't buffer solutions return to equilibrium? Suppose I want to make a buffer solution in any of the three ways possible with dihydrogen phosphate as my weak acid. In the first way, a certain ratio of the weak acid and its conjugate base are ... 3answers 86 views ### Equilibrium for very small amounts of reactants Is there any difference in the concept of equilibrium when it comes down to dealing with extremely small amounts of reactants? Say we have$$\ce{A + B <=> C + D}$$and K_c is 100,000. If ... 2answers 103 views ### How does the equilibrium shift when concentration of reactant and product are increased simulatenously Before answering my question, take a look at this example$$\ce{2NOCl <=> 2NO + Cl2} Let's suppose I have 2 mol/l $\ce{NOCl}$, 2 mol/l $\ce{NO}$, and 1 mol/l $\ce{Cl2}$ in a closed system. ...
e.g. Citric Acid and Trisodium Citrate $\ce{H3C6H5O7 <=>[ka_1] H2C6H5O7- + H+ <=>[ka_2] HC6H5O7^2- + H+ <=>[ka_3] C6H5O7^3- + H+}$ Using the definition of Ka and substituting for ...