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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Ksp calculation of Cr(OH)2

At 25 °C, 10.24 mg of $\ce{Cr(OH)2}$ are dissolved in enough water to make 125 mL of solution. When equilibrium is established, the solution has a pH of 8.49. Estimate $\ce{K_{sp}}$ for $\ce{Cr(OH)2}$ ...
-4
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1answer
22 views

Stability constant for metal ion complex using reduction potential [on hold]

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}\\ ...
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27 views

Equilibrium Reaction for 2ICl -> I2 + Cl2? [on hold]

For the equilibrium equation $\ce{2ICl_{(g)}->I2_{(g)} +Cl2_{(g)}}$, the equilibrium constant is $K_{\mathrm{c}}=0.250$ at a certain temperature. The starting concentration of $\ce{ICl}$ is ...
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2answers
30 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 ...
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33 views

Is it at equilibrium? [closed]

In a flask initially containing colorless molecules of $\ce{N2O4}$, the brown color characteristic of $\ce{NO2}$ appears and the color steadily becomes darker, is it at equilibrium?
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1answer
47 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} = ...
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50 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.
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37 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
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0answers
36 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 ...
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1answer
41 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
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1answer
57 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 + ...
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1answer
45 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
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1answer
21 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 ...
7
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1answer
45 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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26 views

Hydrolysis Of Amphiprotic Anion

Can someone please proove the formula for Hydrolysis Of Amphiprotic Anion in both cases when cation is hydrolysed and when cation(in the salt) is not hydrolysed. On the net it is directly stated that ...
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0answers
25 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( ...
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3answers
857 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 ...
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1answer
32 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
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1answer
45 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
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1answer
68 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
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1answer
59 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 ...
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53 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 ...
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1answer
34 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 ...
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1answer
31 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 ...
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1answer
18 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 ...
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1answer
79 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 ...
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1answer
155 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 ...
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38 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 + ...
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185 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 ...
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21 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 ...
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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 ...
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48 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 ...
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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 ...
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1answer
61 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 ...
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1answer
41 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 ...
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2answers
35 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 $-1,42$?
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25 views

If we mix Ice and water (both at 0 degree Celsius), does their quantity remain constant?

I was wondering that whether Ice and water mixed (both at 0 degree Celsius) undergo a change in their concentration or not. If not, then does it has nothing to do with equilibrium constant? ...
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Does the added component (intended to disturb equilibrium) always ends up being more than the original amount, in the new equilibrium?

The title can be a little unclear. But what I am basically saying is say we add a reactant to a reaction to push the reaction forward toward the product side, that reactant which was increased in ...
2
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1answer
45 views

Finding equilibrium concentrations, trouble simplifying equation

For $\ce{CO (g) + H2 (g) <=> CH2O (g)}$ with Kc = 0.068 @ 273K initial concentrations being $\ce{[CO]}$ = 1.25M, $\ce{[H2]}$ = 2.00M, $\ce{[CH2O]}$ = 1.00M I did $\frac{1.00}{((1.25)(2.00)} = ...
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40 views

How to calculate the sulfanediide concentration at equilibrium in a saturated hydrogendisulfide solution at pH 6? [closed]

What is the $\ce{S^{2-}}$ concentration in a saturated solution (0.10 M) of $\ce{H2S}$, in which the pH has been adjusted to 6.00 by the addition of $\ce{HCl}$? For $\ce{H2S}$, $K_{a1} = 1.1 \cdot ...
0
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1answer
31 views

Finding Kp at another temp with /\Hrxn [closed]

Took a pic of the paper I tried it on it on, has the exact problem description written at top, and what I tried. Figured that would be easier then typing all that. The answer is supposed to be 2.0.
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2answers
65 views

How to calculate pH of a solution with two dominant equilibria?

Say you have acid X for which $K_a(X)$ = 1E-7 and acid Y for which $K_a(Y)$ = 0.8E-7. In separate solutions, it would be easy to calculate $[H^+]$ because there would be only one dominant equilibrium. ...
2
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1answer
63 views

How to calculate the concentration of NO at equilibrium?

$\ce{N2(g) + O2(g) <=> 2NO(g)}$, $K_c = 4.1 \cdot 10^{-4} (T=2000~^\circ\mathrm{C})$ What is $\ce{[NO]}$ when a mixture of $0.20~\mathrm{mol}$ $\ce{N2(g)}$ and $0.15~\mathrm{mol}$ ...
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2answers
43 views

What is the difference between K and Kp in the equilibrium equation?

In this equilibrium equation, $$K = K_p\cdot (\mathcal{R}T)^{-\Delta n}$$ what does $K$ represent in comparison to $K_p$? It seems to me that they'd both be equilibrium constants, but how are they ...
4
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1answer
358 views

Are all strong bases alkalis?

In my text book, it says that strong bases are alkalis because they fully dissociate in aqueous solution. But I'm not too sure of this. Can you not have a weak alkali? And can you not have a strong ...
2
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1answer
59 views

Solid and Liquid Equilibrium [duplicate]

I understand why solids and liquids are not included in the $K_{eq}$ expressions. However, I'm wondering what the $K$ value for a reaction involving only solid or liquid reactants and products looks ...
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1answer
44 views

How to calculate the equilibrium concentration from initial concentrations of the substrates? [closed]

Consider the following equilibrium: $$\ce{2NOCl~(g) <=> 2NO~(g) + Cl2~(g)}$$ with $K = 1.6 \cdot 10^{–5}$. $1.00~\mathrm{mol}$ of pure $\ce{NOCl}$ and $0.989~\mathrm{mol}$ of ...
3
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2answers
114 views

How can pKas differ across similar protons of the same atom?

For example, citric acid has three acidic protons, all of which are carboxylic acids. Despite being part of the same functional groups, they all have very different pKas. Why (and how?) is this?
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42 views

Does a change in partial pressure for a gas-solid reaction, changes the equilibrium?

This is my reaction, $$\ce{Cd (g) + 1/2 Te2 (g) -> CdTe (s)}.$$ Considering the solid CdTe, $$K = P_{\ce{Cd}}^\mathrm{Eq}\cdot \left(P_{\ce{Te}}^\mathrm{Eq}\right)^{\frac{1}{2}}$$ I only have ...
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1answer
55 views

Spontaneity of reversible chemical reactions - Both sides?

Does the reversibility of a chemical reaction make it spontaneous from both sides also? (i.e.: forward & backward reactions) If not then is there any relationship between $\Delta G$ of forward and ...