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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What's the Kp value?

A mixture of $1\ \mathrm{g}$ of $\ce{H2(g)}$ and $1.06\ \mathrm{g}$ $\ce{H2S(g)}$ in a $0.5\ \mathrm{L}$ flask come to equilibrium at $1670\ \mathrm{K}$. At equilibrium, there are $8\times10^{-6}\ ...
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29 views

pH of a double buffer

If $1,2,3,4$ moles of $\ce{H3PO4}$,$\ce{NaH2PO4}$,$\ce{Na2HPO4}$ and $\ce{Na3PO4}$ respectively are mixed together to form an aqueous solution of $1$Litre , resulting $\ce{pH}$ is? This question has ...
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0answers
32 views

The behaviour of Ag3PO4 in solution

To a 1L flask, we add $4.1900\mathrm{g}$ ($0.01001\ \mathrm{moles}$) of $\ce{Ag3PO4}$, then fill it up with water. Knowing the following constants, we are asked to find the concentration of all ...
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1answer
83 views

Relationship between pKa and pKb

The $\mathrm{p}K_\mathrm{a}$ of $\ce{NH3}$ is $38$. Does it stand for the following equilibrium: $$\ce{NH4+ <=> NH3 + H+} \tag{1}$$ With $K_\mathrm{a} = 10^{-38}$ for reaction $(1)$, indicating ...
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2answers
220 views

Is it possible for one of reactants to deplete before achieving equilibrium

Consider the following reaction where $\ce{A}$ & $\ce{B}$ reacts to produce $\ce{C}$ & $\ce{D}$. $$\ce{ A(g) + B(g) <=> C(g) + D(g)}$$ Is it possible for $\ce{A}$ or/and $\ce{B}$ to ...
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0answers
27 views

Equilibrium Problem Involving Solids: Faulty?

I am convinced that this is a faulty problem: $\ce{2 Cu + S -> Cu2S}$ For the reaction above, $\Delta H$, $\Delta S$, and $\Delta G$ are all negative. Which of the substances would ...
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2answers
28 views

Why is iron(II) fluoride thermodynamically favorable when dissolved in acid?

I am reviewing for the AP Chemistry test, and the question is this $$ \ce{FeF2(s) <=> Fe^2+(aq) + 2F^- (aq) } \quad K_1 = 2\times 10^{-6} $$ $$ \ce{F- (aq) + H+ (aq) <=> HF(aq)} \quad ...
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43 views

Apparent solubility of Ag2C2O4 in a buffer solution

We take the following quantities and mix them together: $20\mathrm{mL}$ solution of $\ce{AgNO3}$ $0.001 \frac{\mathrm{moles}}{\mathrm{dm^3}}$ $20\mathrm{mL}$ solution of $\ce{H2C2O4}$ ...
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21 views

Spontaneous and Favoured Chemical Reactions

I have some problems in understanding what is the difference between a reaction which is spontaneous and a reaction which is termodynamically favoured. I'm looking at the equation of Gibbs Free ...
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1answer
54 views

The effect of reactant concentration on when equilibrium is established

Take the equation $$\ce{A(g) <=> B(g)}$$ where the reaction is first order with respect to A. The rate law is thus $$\frac{\mathrm d[\ce{A}]}{\mathrm dt}=-k[\ce{A}]$$ Say you run the reaction, ...
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19 views

A problem from ionic equilbrium [on hold]

The solubility product of Calcium hydroxide at 298 K is 0.0000442.A 500 ml of saturated solution of calcium hydroixde is mixed with equal volume of 0.4 M sodium hydroxide.How much calcium hydroxide in ...
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54 views

How to find deltaG when given the equilibrium constant and temperature?

For the reaction, $$\ce{N2O4(g) <=> 2NO2(g)}$$ the equilibrium constant in terms of concentration, $K_c$, at $100~^\circ\rm C$ is $0.36$. What is ${\rm\Delta} G$? I used the equation ...
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1answer
27 views

A doubt in chemical equilbrium

say we have a reaction N2O4 reversible 2NO2 for this reaction,if initial number of moles of N2O4 is 'a' can we write t = 0 a - at equilbrium a-x 2x similarly can we do the same for pressure? i.e. ...
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45 views

A problem in ionic equilbrium

Question 1998(b) My attempt: I thought that $\ce{AgCl}$ would yield $\ce{Ag+}$ and $\ce{Cl-}$ ions, whose concentration can be found from $K_{sp}$ as $\sqrt{K_{sp}}$. This $\ce{Ag+}$ reacts with ...
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1answer
11 views

Acid-Base Equilibrium Concept question

I have a question about when to use H3O+ and when to use the actual compound. I'm not really sure how to word this question so I'll show you an example of what I mean. Example of using H3O: "A ...
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1answer
53 views

Understanding effect of ph on solubility of salt

In the following picture why Ksp is not simply S2- ? Why is f included with one species only? Please explain the last part. What does f represent and why it is used in molar solubility?
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1answer
24 views

Concentration and volumes

In the reaction: $$\ce{H2SO4 +CaCO3 \to CO2 + H2O + CaSO4}$$ Does altering the concentration of the sulfuric acid change the volume of the carbon dioxide produced [the volume of the sulfuric acid is ...
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18 views

Total Pressure in equilibrium

I got a very confusing question. I need to calculate the total pressure in a reactor. The gases are Hydrogen and Nitrogen in a 3:1 ratio that reacts to Ammonia. All the final mole fraction of those ...
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1answer
75 views

Determine if an acid base reaction will occur

I'm wondering why some acid base reactions occur, let's say for example: $$\ce{CH3CH2OH + H2O <<=> CH3CH2O- + H3O+}$$ Why does this reaction occur, because the alkoxide ion is a really ...
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2answers
40 views

Change in equilibrium when not all product and reactant are increased

$$\ce{2NOCl <=> 2NO + Cl2}$$ What will be the effect on equilibrium concentration of $\ce{NOCl}$ when equal moles of $\ce{NOCl}$ and $\ce{NO}$ are introduced in the mixture at constant ...
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15 views

Raoult's Law and Equilibrium

Vapor pressure is numerically the equilibrium constant of a liquid-vapor equilibrium. And when there's a simultaneous equilibrium of two separate reactions both the equilibria need to be satisfied ...
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1answer
28 views

Why do we not include water in equilibrium expression calculations? [duplicate]

Why do we not include water in equilibrium expression calculations? And can you go into detail on why pure liquids and solids have a constant concentration as well, please and Thanks.
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1answer
41 views

Why does a buffer work best at the pH closest to its pKa?

I think I'm having trouble understanding exactly how the pKa relates here on a conceptual level. For example I know that carbonic acid works somewhat well as a buffer at pH near 7, since its pKa is ...
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1answer
23 views

Determining the temperature at which 90% of the reactants in a equilibrium have reacted

I have the following problem I am stuck on, specifically the last bit (iii). The first parts are fairly trivial and I have arrived at the following equation to determine the temperature: ...
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11 views

Physical chemistry and pH [duplicate]

My question may be strange a little but how could dilution change the pH, For example:if we have an acid solution and we add water the pH increases, but if the water has equal concentrations of H+ and ...
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0answers
27 views

Dimerisation effect on distribution ratio?

The question reads: "Carboxylic acids (RCOOH) form dimers in solvents of low polarity such as benzene and carbon tetrachloride. Using suitable equations, explain the effect of association on the ...
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1answer
49 views

Unique Solubility Expression for Sulfide Salts

While looking at aqeuous $\ce{K_{sp}}$ values in the back of my textbook, I noticed that there is a asterisk by all of the sulfide compounds (such as $\ce{HgS}$), and the asterisk says, "For a ...
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1answer
21 views

Mixing a Tagged Sample of Lead Iodide with another Iodide Salt [closed]

A sample of sparingly soluble $\ce{PbI_2{(s)}}$ containing radioactive $\ce{^{133}I}$ is added to 0.10 M $\ce{KI_{(aq)}}$ and stirred overnight, what happens? I The radioactivity of the liquid phase ...
2
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0answers
16 views

Calculate the flow rate in the steady state of a dynamic equilibrium

I have the following situation: I am interested of the reactions rate of an enzymatic reaction, depending of the substrate concentration. The thing is, that I don't add the substrate directly to the ...
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13 views

How to calculate the gas pressure of HCl over a saturated CuCl2 solution

I have a concentrated solution of $\ce{CuCl2}$ ($<200~\mathrm{ml}$, surface area $2100~\mathrm{cm^2}$). I saw a note about protecting metal equipment from $\ce{HCl}$ attack in the room ...
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1answer
119 views

How is the association/ dissociation constant derived?

I came across the following formula to find the association of a solute in particular solvent. Suppose the concentration of the solute given in water (or in some other solvent in which it does not ...
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14 views

Halving the electrolyte concentrations of a voltaic cell

Say you have a standard voltaic cell with $Q=1$. The concentrations of both the electrolytes are at 1.0 M. If you halve the concentrations in both to 0.5 M, $Q$ still equals 1 and ...
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1answer
22 views

The equilibrium constant of a reaction only involving pure solid or liquid

How to calculate the equilibrium constant of a reaction only involving pure solid or liquid. For example reaction $$\ce{S(s) + Hg(l) -> HgS(s)}$$ or $$\ce{S(s) + Mg(s) -> MgS(s)}$$
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39 views

Finding Ka given H+ value and molarity

Can someone solve this problem? I just need to confirm my solution A $\rm1.0~M$ solution of acid has $$\ce{[H+]} = \rm 1\times10^{-2}~M$$ Find the value of Ka. My solution is: $$\ce{[H] = ...
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29 views

Do solids affect equlibrium?

After doing a calculation on $K_{C}$, I was told that solids do not affect the calculation. This is confusing me. Is there a specific reason why solids do not affect the equilibrium shift? Thanks.
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1answer
37 views

How can you explain the energy change in this phenomenon?

Tagged is the diagram of the apparatus used in this thought experiment. Pure water is taken in one side of the beaker and a solution of common salt in water in the other. After a very long time, the ...
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20 views

Preventing precipitation of Ca(HPO4)2

Determine the $\ce{[H+]}$ needed to just prevent precipitation by $\ce{H2PO4^-}$ in a 0.25 M $\ce{H3PO4}$ solution that has $\ce{[Ca^{2+}]}$ = 0.15 M. The $K_{a1}$ of $\ce{H3PO4}$ is $7.1 \times ...
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1answer
39 views

Calculation of Ka and pH

$$\ce{H3PO4 <=> H+ + H2PO4-}$$ $$K_{\mathrm a1} = 7.4\times10^{-3}$$ $$\ce{H2PO4- <=> H+ + HPO4^2-}$$ $$K_{\mathrm a2} = 6.2\times10^{-5}$$ $$\ce{HPO4^2- <=> H^+ + ...
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0answers
15 views

What are the equilibrium composition of ethane burned in air as lean mixture?

This is one of my attempts, I have tried 3 ways to get to the answer. As you can see we have 5 unknowns so we need 5 equations to solve them. The nitrogen won't dissociate (that is an assumption ...
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1answer
44 views

Precipitaiton of aragonite

I'm not positive what this questions is asking. The prompt says "Write balanced equations for the following processes. Chemical species should be the dominant ones at the given $\mathrm{pH}$. Show ...
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1answer
52 views

Why is Kc not affected by change in pressure?

Why is Kc not affected by change in pressure? I know the mathematical explanation but I don't really understand the reason why when only looking at Kc (the explanation I know is with reference to Kp, ...
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1answer
32 views

When can we add multiple reactions to compute yield of products in an equilibrium?

It is widely known that we can add multiple equilibrium reactions to obtain a net reaction and a corresponding equilibrium constant for the net reaction. However, I am not sure of exactly when this ...
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7 views

Change in pressure of heterogeneous equilibrium

Basically, how do the solids/liquids (which don't change pressure) affect the way the reaction responds to the change in pressure? for example, if you increased the pressure of this equilibrium ...
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61 views

How does the equilibrium change upon adding acid or base?

In an aqueous solution of sodium carbonate, $\ce{Na2CO3}$, this equilibrium occurs: $$\ce{CO3^2- (aq) + H2O (l) <=> HCO3 (aq) + OH^- (aq)}$$ How would the addition of solid sodium ...
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2answers
38 views

How does concentration affect The Position Of Equilibrium?

I was taught that when the concentration of the reactants is greater than the concentration of products then the position of equilibrium is shifted towards the left. However when I used La'Chateliers ...
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2answers
218 views

pH of a buffer made with H3BO3 and KH2BO3

The Problem Calculate the pH of a buffer that is 0.200M $\ce{H3BO3}$ and 0.122M $\ce{KH2BO3}$. The $K_a$ for $\ce{H3BO3}$ is $7.3*10^{-10}$ What I Tried For each of these methods, I used 0.200M as ...
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48 views

solubility of silver benzoate

The ionisation constant of benzoic acid is $6.46*10^-5$ and Ksp of silver benzoate is $2.5*10^-13$. How many times is silver benzoate more soluble in a buffer solution of pH-3.19 as compared to water. ...
3
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1answer
35 views

Le Chatelier's with pure solids and liquids

In the following general reaction, $$\ce{A(s) <=> B(g) + C(g)}$$ since adding a pure solid is not supposed to shift the equilibrium in any way, does that mean that I can essentially remove all ...
3
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1answer
47 views

Is HCl(l) acidic?

If in a reaction mixture HCl is given in liquid phase, will it behave as an acid ? I know that an aqueous solution of HCl is acidic but am confused about the liquid phase.
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22 views

Shape of the blood CO2 dissociation curve

What equation determines the shape of the blood $\ce{CO2}$ dissociation curve? I know that since it factors all possible forms of $\ce{CO2}$ carriage, there are a bunch of factors (e.g. Henry's law, ...