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
4 views

Ionization and concentration

If we consider an acidic solution like HF if we increase concentration of HF in the solution according to le chtelier's principle the equilbrium shifts toward the product to decrease the ...
0
votes
0answers
8 views

How to find the value of $K_c$?

This is part of my homework. Given the chemical equation : $$\ce{Sb2S3_{(s)} + 3H2_{(g)} <=>2Sb_{(s)} + 3H2S_{(g)}}\text{ }K_{p}=0,429\text{ at }713\text{K}$$ What is the value of $K_c$ ...
0
votes
1answer
17 views

What exactly is the requirement (in terms of saturation) for a reaction to be at equilibrium?

A saturated solution is a solution that contains the max amount of solute able to be dissolved. However, can't a solution still be at equilibrium if you add more solute to a saturated solution as long ...
1
vote
1answer
31 views

Can rate constant for forward reaction be equal to rate constant for backward reaction? [duplicate]

For a particular reaction, can we have $K_c = 1$? My confusion arised when I was studying the effect of temperature on $K_c$ . I see that the temperature must affect forward and backward rate ...
0
votes
0answers
25 views

Hydrogen disulfide heterogenous equilibrium

I have been struggling with the following problem for quite a while: I was able to calculate the Gibbs free energy and the equilibrium constant, using the formula $$ΔG = -RT\ln K$$ and ...
0
votes
2answers
44 views

Delta G in an equilbrium reaction(forward and backward)

Consider a reaction say $$\ce{A + B <=> C + D}$$ Now $\Delta G$ for the forward reaction is: $$\Delta H - T\Delta S$$ For the backward reaction $\Delta H$ and $\Delta S$ are clearly the same ...
0
votes
2answers
48 views

Equation of water at triple point

I was thinking about what exactly happens at the triple point of water, and what could be the effect of adding solutes/solvents. I feel we can represent the triple point using the following ...
0
votes
0answers
22 views

how to Find $P_{tot}$ Given that $K_p = 28.5$ and the partial pressure at equilibrium

I have the equilibrium equation : $4KO_2{_{(s)}} + 2CO_2{_{(g)}} \ce{<=>} 2K_2CO_3{_{(s)}} + 3O_2{_{(g)}}~~k_p = 28.5 ~at ~25C$. Given that The partial Pressure of $CO_2$ is $0.191~atm$ at ...
1
vote
2answers
75 views

Deprotonated form of phenolphthalein

The wikipedia page states clearly that the coloured form of phenolphthalein is the one with two protons removed. What is the evidence that phenolphthalein loses both protons in basic solution? And ...
0
votes
0answers
16 views

How to account for the common ion effect on osmolarity quantitatively?

In adjusting the osmolarity of a solution of Benzalknonium Cl, Disodium Editate, and Disodium borate/boric acid buffer to be isotonic (about 290 mOsm), the addition of NaCl showed unexpected behavior, ...
-1
votes
0answers
38 views

Is Anhydrous Sulfuric Acid Really Impossible? [closed]

I was reading the wikipedia article for Sulfuric acid, and came across the following table: I realize that this species is highly self protonating, and assuming this data to be experimentally ...
1
vote
1answer
32 views

How to explain that an increase in temperature favours an endothermic reaction?

I'm trying to explain how a change in temperature favours an endothermic/exothermic reaction from a collision theory point of view, but I'm not really familiar with the concept just yet. For an ...
1
vote
1answer
15 views

Question about change in pressure and change in temperature for system at equilibrium

I was reading my Chemistry textbook and I noticed that it stated that for a system at equilibrium: At constant temperature, reducing the volume of gaseous equilibrium mixture causes the system to ...
0
votes
1answer
28 views

Is there a name, or any specific jargon for a precipitation equilibrium involving a solid reactant?

Let's say you have some ions in solution, for example Na+(aq) and OH-(aq), and some partially dissolved solid, MgCO3(s), Mg+2(aq) and CO3-2(aq), which precipitates Mg(OH)2(s) until equilibrium. So ...
1
vote
2answers
89 views

Will NaF + CaCO3 precipitate much CaF2?

If I mix sodium fluoride, calcium carbonate powder, and water, under what conditions (if any) would there be an equilibrium? I.e. assume we start out with fully dissociated $\ce{Na+(aq) + F-(aq)}$, ...
5
votes
2answers
117 views

Kinetics of converting a water + heavy water mixture to HDO

Imagine an initial 50%-50% mixture of normal ($\rm H_2 \rm O$) and heavy water ($\rm D_2 \rm O$). I think, simply mixing them, the result will exponentially converge to an equilibric state, where ...
1
vote
1answer
30 views

How to manage complex equilibria when studying a mecanism?

Consider a complex multistep reaction mechanism with several intermediates. There are multiple possible pathways as well as equilibria in solution. One wants to study the reaction mechanism using ...
-1
votes
2answers
29 views

In reversible processes in dynamic equilibrium why do we only see the products and not the reactants?

If both forward and backward reaction rates are equal why is it that only the products are visible to a naked eye?
-1
votes
0answers
18 views

Why is the concentration of solids taken as 1 in the equation of equilibrium constant [duplicate]

I can understand why their concentrations are constant but why is it taken as 1.
0
votes
1answer
34 views

Finding Ka of a monoprotic weak acid from pH and concentration of added sodium salt

A solution of $\pu{0.36 M}$ of the sodium salt of a generic monoprotic weak acid $\ce{HA}$ has a $\mathrm{pH}$ value of $8.782.$ $K_\mathrm{a} = ?$ Why doesn't the following formula work in this ...
0
votes
0answers
50 views

Modifications and alterations in the state of chemical equilibrium

Let us consider that we have a mixture of gases, considered ideal, that is in balance. Like, for example, $$3\ce{NO} (g) \rightleftharpoons \ce{N2O} (g) + \ce{NO2}(g)$$ If we consult the ...
0
votes
2answers
56 views

pH of amphoteric species

For a solution of $\ce{HA-}$, I have seen the following approximations for the $\mathrm{pH}:$ $$\mathrm{pH} = \frac{1}{2}(\mathrm{p}K_\mathrm{a1} + \mathrm{p}K_\mathrm{a2})\tag{1}$$ $$\mathrm{pH} = \...
4
votes
1answer
53 views

Has anyone encountered the use of Omega to represent equilibrium?

One of my lecturers last year (a pharmacologist by training) used the symbol $\Omega ^m$ as a shorthand for equilibrium. He implied it was common practice but I've never come across it elsewhere. I ...
0
votes
3answers
91 views

How to simplify these system of equilibrium equations

What is the pH when $0.025$ mol $\ce{NiCl2}$ is added to $\pu{1.00 L}$ of a $\pu{0.100 M}$ solution of $\ce{HCN}$, if the formation constant for $\ce{Ni(CN)4^2-}$ is $K_f=\pu{1.0e22}$, and the $K_a$ ...
1
vote
0answers
20 views

Determining relative changes in a generic reaction

I'm an electrical engineer by trade and I am trying to solve a problem I found in some old course notes. Given is a reversible, homogeneous reaction: $\ce{ A + 2B <=> C + 3D }$ A solution of ...
2
votes
1answer
53 views

How does LeChatelier’s principle (which makes qualitative predictions) relate to the quantitative changes observed when an equilibrium is disturbed?

Le Chatelier formulated his principle in 1884; it predicts the direction in which equilibrium is re-established after it has been disturbed by an external cause. How does this qualitative principle ...
2
votes
1answer
73 views

Finding the concentration of each ion in saturated solution of lead(II) hydroxide

Question If the solubility of $\ce{Pb(OH)2}$ is $\pu{0.155 g/L},$ then the concentration of each ion in a saturated solution of $\ce{Pb(OH)2}$ is A. $[\ce{Pb^2+}] = \pu{0.155 g/L}$ and $[\ce{...
1
vote
1answer
37 views

How to calculate the amount of sodium sulfate needed to lower the silver ion concentration of a saturated silver sulfate solution?

How many moles of $\ce{Na2SO4}$ we have to add into a saturated $\pu{0.5 L}$ solution of $\ce{Ag2SO4}$ so that the concentration of $\ce{Ag}$ is $\pu{4.0 \times 10^-3 M}$? ($K_\mathrm{sp} = 1.4 \times ...
-1
votes
1answer
118 views

Le Chatelier's principle and van 't Hoff equation

When temperature is increased, then according to Le Chatelier's principle the reaction will move in the direction where energy is absorbed. I can understand this, but there is also another fact that ...
3
votes
2answers
158 views

Use of Concentration for pH

When we find the pH of a solution, do we use normality or molarity? My teacher said that if the compound is present by itself, we can use normality but in all other cases we should use molarity. Can ...
0
votes
1answer
85 views

Calculating pH of rain water

The concentration of $\ce{SO2}$ in the atmosphere over a city on a certain day is $\pu{10 ppm}$. Given that solubility of $\ce{SO2}$ in water is $\pu{1.3653 mol L-1}$ and $\mathrm{p}K_\mathrm{a}$ of $\...
2
votes
2answers
68 views

Calculating equilibrium concentrations of silver and halide ions

$\pu{500 ml}$ of $\pu{0.01 M}$ $\ce{AgNO3}$ is mixed with $\pu{500 ml}$ of solution containing $\pu{0.1 M}$ $\ce{NaCl}$ and $\pu{0.1 M}$ $\ce{NaBr}$. $K_\mathrm{sp}$ of $\ce{AgCl}$ is $10^{-10}$ and $...
4
votes
1answer
184 views

Is chromate a suitable indicator for the titration of Ag⁺ with Cl⁻?

To titrate $\ce{Cl-}$ with $\ce{Ag+}$ we use chromate $\ce{CrO4^2-}$ as an indicator. The titration reaction is: $$\ce{Ag+ + Cl- <=> AgCl}\tag{R1}$$ $$K_1 = \frac{1}{K_\mathrm{sp}(\ce{AgCl})} =...
-1
votes
1answer
32 views

Why does a reaction move both forward and backward in dynamic equilibrium? [closed]

As a kid I never imagined equilibrium to be a state where both forward and backward reactions keep taking place. Although, by seeing one cannot tell. Why is it that both forward and backward reactions ...
5
votes
1answer
46 views

If volatility depends on intermolecular forces, then why in Raoult's law, two substances have different volatility?

I have a doubt, Ideal solutions are solutions where intermolecular forces between solute-solute and solvent-solvent are nearly equal to solute-solvent. Since intermolecular forces between A-A = B-B, ...
-1
votes
1answer
27 views

Calculating partial pressure with 3 equilibrium equations [closed]

So my friend had sent this question to me some days ago and it seems I still am not able to solve it. I am confused whether the amount of A that dissociates in the first equation would account for the ...
2
votes
1answer
26 views

Ligand substitution reaction in coordination compounds

I know that the following substitution reaction can take place: $$\ce{[Cu(H2O)4]^2+ (aq) + 4NH3 (aq) -> [Cu(NH3)4]^2+ (aq) + 4H2O (l)}$$ This is because ammonia is a stronger ligand than water. ...
1
vote
2answers
90 views

What is wrong in this argument that dG must always be zero?

Under constant temperature and pressure, the change of the Gibbs free energy can be written as $$\mathrm dG_\textrm{sys} = \mathrm dH_\mathrm{sys} - T\,\mathrm dS_\mathrm{sys}$$ And in the textbook ...
0
votes
1answer
42 views

Increasing temperature in system of dynamic equilibrium

According to the article Summary of Le Chatelier's Principle on dynamicscience.com.au, for the process $$\ce{N2(g) + 3 H2(g) <=> 2 NH3(g)}\quad ΔH = \pu{-92 kJ/mol}$$ the forward reaction is ...
4
votes
3answers
108 views

Dynamic equilibrium in unsaturated solutions

One standard definition of equilibrium in beginner chemistry is that for a reversible reaction, (dynamic) equilibrium has been achieved when the rate of the forward and backward reactions are equal. ...
0
votes
0answers
19 views

Rate Equation of Chemical Traffic Light (NaOH + Glucose + H20 + Indigo Carmine)

I am trying to find the Rate Equation of the Chemical Traffic Light Experiment. Wikipedia says the Blue Bottle Experiment (similar, but uses a different dye) has the following orders: The reaction ...
0
votes
0answers
20 views

Ka for reaction from tables [duplicate]

For the reaction below: NH4+ + H2O -> NH3 + H30+ I have the following values from a table to use: And in the solution manual they tell me to use the Ka for this reaction. Why is this? Why do we ...
8
votes
2answers
1k views

What is the difference between chemical equilibrium and dynamic equilibrium?

Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in the concentrations of product and reactant. Dynamic equilibrium from ...
1
vote
0answers
36 views

Thermochemical data for thiocyanatoiron(III) ion

I am currently writing a lab report about the formation constant of $\ce{FeSCN^2+}.$ All I could find online was a formation constant at $\pu{25 °C}$ $(890),$ which was 70% higher than the ...
-1
votes
1answer
20 views

Chemical equilibrium [duplicate]

When calculating equilibrium constant with partial pressures if there is a solid involved should we consider it in the total number of moles in mole fraction?
0
votes
1answer
26 views

What exactly causes equilibrium to shift when pressure is decreased? [duplicate]

Take the reaction: $$\ce{N2(g) + 3 H2(g) <=> 2 NH3(g)}$$ If pressure is decreased, equilibrium shifts to the left because it has more moles. I understand the basics of why this is, i.e. due to ...
6
votes
0answers
50 views

Using Le Chatelier's Principle to Change Mechanical Energy to Chemical Energy

I was interested in an application of Le Chatelier's principle, where an increase in pressure could result in a decrease in the moles of gas. In particular, a situation where when the pressure ...
0
votes
2answers
51 views

Equilibrium of an electrochemical cell [closed]

I am quite new to the field. So try to figure out what is meant by the equilibrium state of an electrochemical cell? Is it, where both half cells passing the same number of electrons to either side? ...
3
votes
1answer
74 views

Gibbs energy derivative vs equilibrium for aqueous reaction

I am trying to find the Gibbs-energy equilibrium for the reaction $$\mathrm{A}+\mathrm{B}\rightleftharpoons\mathrm{C}.$$ According to most sources the equilibrium concentrations in an ideal solution ...
4
votes
0answers
36 views

How are σ+ values in Hammett Plots calculated?

First of all, I know a similar question has already been asked & answered about σ values in general, however, I am not 100 % sure this answer is correct for the following situation. So for the σ ...