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Use the following information for both of the next two questions We can easily …

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Wize University Chemistry Textbook > Equilibrium

Le Chatelier's Principle

3 Activities

Wize University Chemistry Textbook > Equilibrium

The Equilibrium Constant (K)

4 Activities

Use the following information for both of the next two questions

We can easily observe shifts in the equilibrium of the following reaction because the reactants and products have different colours.

2NO2(g)⇌N2O4(g)Dark redColourless\def\arraystretch{1.5} \begin{array}{ccc} &2NO_2(g)&⇌&N_2O_4(g) \\ &\rm Dark \ red && \rm Colourless \end{array}

The equilibrium constant for this reaction was determined for several temperatures.

T(K)KC2737329817\def\arraystretch{1.5} \begin{array}{c|c} T (K) &K_C \\ \hline 273 &73 \\ 298 &17 \\ \end{array}
Predict and rationalize the colour of the reaction mixture when cooled below 0ºC.
More Le Chatelier's Principle Questions:
Le Chatelier's Principle
In an esterification reaction, a carboxylic acid and an alcohol react to form an ester and water. This reaction establishes an equilibrium because the reverse process can also occur. If the water is allowed to boil and leave the system as water vapour, how will the equilibrium respond?
Given the following exothermic reaction, decide which direction the equilibrium will shift (if any) in each scenario.
CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)
Consider the following reaction:
2 As(s) + 6 NaOH(aq) → 2 Na3AsO3(aq) + 3 H2(g)
If the pressure of the reaction is increased, how will this change the equilibrium? Why?
Consider the following reaction:
2 As(s) + 6 NaOH(aq) → 2 Na3AsO3(aq) + 3 H2(g)
If the produced H2 gas is removed from the reaction upon being produced, which direction will this drive the equilibrium? Why?
Look at the following reaction.
BaCrO4(s) <----> Ba2+(aq) + CrO42-(aq)
If PbCrO4 is added to the solution, which direction would we expect the equilibrium to shift?
Le Chatelier's Principle
Given the following exothermic reaction, decide which direction the equilibrium will shift (if any) in each scenario.
CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)
Le Chatelier's Principle
Consider the following reaction at equilibrium in a closed container:
2HgO(s)⇌2Hg(l)+O2(g)ΔH°=+181.4kJ2HgO(s) \rightleftharpoons 2Hg (l) + O_2 (g) \qquad \Delta H° = +181.4kJ
The partial pressure of O2 may be increased by:
Le Chatelier's Principle
Consider the information provided in the table on the right for the following reaction:
H2(g)+Cl2(g)⇌2HCl(g)H_2(g) +Cl_2(g)\rightleftharpoons 2HCl(g)
Which of the following statement is true?
Le Chatelier's Principle
Which of the following changes would allow the formation of more CrCI3? Assume the system is at equilibrium before these changes are done.
4Cr(s)+3CCl4(g)⇌4CrCl3(g)+3C(s)ΔH=26.9kJ4Cr(s)+3CCl_4 (g)\rightleftharpoons4CrCl_3 (g)+3C(s)\qquad ΔH = 26.9 kJ
Le Chatelier's Principle
For the equilibrium process 2 NO (g) ⇌ N2 (g) + O2 (g), Kc = 2.1x1030 at 20oC and ΔHo = -413 kJ/mol. If O2 is injected into the mixture at equilibrium in a sealed rigid vessel, which of the following changes will occur?
Le Chatelier's Principle
For the equilibrium process 2 BrCl (g) ⇌ Br2 (g) + Cl2 (g), which of the following changes will cause additional Cl2 to be formed.
1. Addition of Br2
ii. Addition of BrCl
For the following reaction at equilibrium, list three ways other than concentration to shift the reaction to favor the formation of products?
2NOBr(g)⇌2NO(g)+Br2(g)                 ΔHorxn=30KJ/mol2NOBr(g)\rightleftharpoons 2NO(g) +Br_2(g) \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \Delta H^orxn=30KJ/mol
Le Chatelier's Principle
Determine the shift in equilibrium when the following changes are introduced to the following equilibrium:
(NH4)(H2NCO2)(S)⇌2NH3(g)+CO2(g)(NH_4)(H_2NCO_2)(S) \rightleftharpoons 2NH_3(g)+CO_2(g)
Volume of the container is expanded by 10 L.
Le Chatelier's Principle
Consider the information provided in the table on the right for the following reaction:
H2(g)+Cl2(g)⇌2HCl(g)H_2(g) +Cl_2(g)\rightleftharpoons 2HCl(g)
Which of the following statement is true?
Le Chatelier's Principle
Which ONE of the following changes will, at least in principle, increase the amount of C6H12O6 (s) at equilibrium in the reaction:
6 CO2 (g) + 6 H2O (l) ⇌ C6H12O6 (s) + 6 O2 (g) ΔHo is positive in the forward direction
Le Chatelier's Principle
Which of the following changes would allow the formation of more CrCI3? Assume the system is at equilibrium before these changes are done.
The equation for the reaction is:
Cr2O3(s)+3CCl4(l) ⇌ 2CrCl3​(s)+3COCl2​(g)
One of the demonstrations in this course was about the effect of temperature in chemical equilibrium. NO2 (a brown gas) was kept in a flask in equilibrium with N2O4 (a colourless gas). When the flask was immersed in liquid nitrogen, the mixture inside became colourless. On the other hand, when the flask was immersed in hot water, the mixture inside was brown. What can you say about the equilibrium: N2O4 (g) ⇌ 2 NO2 (g) from these observations?
Le Chatelier's Principle
Consider the equilibrium 4 NH3 (g) + 5 O2 (g) ⇌ 4 NO (g) + 6H2O (g). Which one of the following statements correctly describes what happens when the described change is made in the reaction vessel? Interpret the arrow symbol → to mean “has the result that … “
Le Chatelier's Principle
For the process: 2 ICl (s) ⇌ I2 (s) + Cl2 (g)
At equilibrium, which of the following changes will cause additional Cl2 to be formed?
Le Chatelier's Principle
For the equilibrium process 2 NO (g) = N2 (g) + O2 (g), Kc = 2.1x1030 at 20oC and ΔHo = -413 kJ/mol. If the temperature of a mixture at equilibrium is increased from 20oC to 30oC, which of the following will occur?
Which of the following statement is correct
Which of the following equilibrium will not respond to a change in container volume?
Le Chatelier's Principle
In an esterification reaction, a carboxylic acid and an alcohol react to form an ester and water. This reaction establishes an equilibrium because the reverse process can also occur. If the water is allowed to boil and leave the system as water vapour, how will the equilibrium respond?
The Haber-Bosch process is the process used to produce industrial quantities of ammonia, most of which is used to make fertilizer.
N2(g)+3 H2(g)⇌2 NH3(g)N_{2(g)}+3\ H_{2(g)}\rightleftharpoons 2\ NH_{3(g)}
The equilibrium shifts left when,
(Duplicated)
For the following reaction predict the change in K when a catalyst is added.
(Duplicated)
For the following reaction predict the direction the equilibrium will shift when the total pressure is decreased?
(Duplicated)
For the following reaction predict the direction the equilibrium will shift when steam is added to the reaction?
(Duplicated)
For the following reaction predict the change in K when the temperature is increased?
(Duplicated)
For the following reaction predict the direction the equilibrium will shift when CO2 is selectively removed?
For the following reaction predict the direction the equilibrium will shift when the pressure of O2 is increased?
Le Chatelier's Principle
Of the following equilibria, only ______ will shift to the left in response to a decrease in volume.
The reaction below is at equilibrium. You want to apply Le Chatelier’s principle to produce a higher quantity of product gases. Which change will accomplish this effect?
CO2 (g) + 2 H2O (l) ⇌ CH4 (g) + 2 O2 (g)
For the equilibrium process 2 NO (g) ⇌ N2 (g) + O2 (g), Kc = 2.1x1030 at 20oC and ΔHo = -413 kJ/mol. If O2 is injected into the mixture at equilibrium in a sealed rigid vessel, which of the following changes will occur?
Le Chatelier's Principle
For the equilibrium process 2 BrCl (g) ⇌ Br2 (g) + Cl2 (g), which of the following changes will cause additional Cl2 to be formed.
1. Addition of Br2
2. Addition of BrCl
Le Chatelier's Principle
For the equilibrium process 2 NO (g) = N2 (g) + O2 (g), Kc = 2.1x1030 at 20oC and ΔHo = -413 kJ/mol. If the temperature of a mixture at equilibrium is increased from 20oC to 30oC, which of the following will occur?
Le Chatelier's Principle
Which of the following changes would allow the formation of more CrCI3? Assume the system is at equilibrium before these changes are done.
Le Chatelier's Principle: Percent dissociation
A solution made by dissolving 0.1 mol of acetic acid in 1.0 L of water is 4.1% dissociated. Which of the modifications below would cause the % dissociation of the acetic acid in the container to increase? (Ka for acetic acid is 1.8×10-5.)
Which of the changes below would result in a shift towards the products if applied to this system at equilibrium?
CO2(g)+C(graphite)⇌2CO(g)CO_2 (g)+C(graphite)⇌2CO(g)
Le Chatelier's Principle
How many of these reactions will shift towards the products, if the size of the reaction container is decreased after equilibrium has been reached?
Le Chatelier's Principle
For the reaction of barium carbonate shown here, which of these changes suggested below will result in a decrease in pH at equilibrium? Assume that the reaction is at equilibrium before making any change, and that there is excess BaCO3 and H2O present.
BaCO3(s)+2H+(aq)⇌Ba2+(aq)+CO2(g)+H2O(l)BaCO_3 (s)+2H^+ (aq)⇌Ba^{2+} (aq)+CO_2 (g)+H_2 O(l)
Le Chatelier's Principle
Use the following reaction scenario to answer the following questions
SO2(g)+Cℓ2(g)⇌SO2Cℓ2(g)ΔrH°<0SO_2(g)+Cℓ_2(g)⇌SO_2Cℓ_2(g)\qquadΔ_rH°<0
You have prepared a container with these compounds and allowed it to come to equilibrium. You now have a choice of different ways to modify your system at equilibrium. Assume that during each of these changes, all other parameters remain constant. Select all that apply.
For the reaction X+Y⇌2ZX+Y \rightleftharpoons2Z, a system at equilibrium is initially prepared. The equilibrium concentrations are given by the following bar chart:
If half of the amount of Z is removed from the system, which of the following bar charts represents the concentrations in the system when it returns to equilibrium?
Over time, quicklime (calcium oxide) reacts with carbon dioxide in the air to produce calcium carbonate, as shown here:
CaO(s)+CO2(g)⇌CaCO3(s)CaO(s)+ CO_2(g)⇌ CaCO_3(s)
Suppose that you want to increase the yield of CaCO3(s) produced by shifting the equilibrium towards the products. Which of these suggested changes would accomplish this? Select all that apply
Which of the following reactions will shift towards the products if the size of the reaction container is increased after equilibrium was reached? Select all that apply.
Consider the endothermic reaction: NH4Cl(s)⇌NH4+(aq)+Cl−(aq)NH_4Cl(s)\rightleftharpoons NH_4^+(aq)+Cl^-(aq). Which of the following does not occur when the reaction temperature is decreased?
Suppose you know that the reaction A⇌BA \rightleftharpoons B is endothermic. What happens to the rates of the forward and reverse reactions when the reaction temperature is increased?
Le Chatelier's Principle: Exothermic Reaction
Carbon disulfide, CS2, and chlorine gas react according to the following exothermic equilibrium reaction:
CS2(g)+3Cl2(g)⇌S2Cl2(g)+CCl4(g)CS_2 (g)+3Cl_2 (g)⇌S_2 Cl_2 (g)+CCl_4 (g)
If a vessel containing a mixture of these compounds starts at equilibrium and is exposed to a change, which of the following statements is TRUE?
Le Chatelier's Principle
Over time, quicklime (calcium oxide) reacts with carbon dioxide in the air to produce calcium carbonate, as shown here:
CaO(s)+CO2(g)⇌CaCO3(s)CaO(s) + CO_2(g) ⇌ CaCO_3(s)
Suppose that you want to increase the yield of CaCO3(s) produced by shifting the equilibrium towards the products. Which of these suggested changes would accomplish this?
More The Equilibrium Constant (K) Questions:
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium: Reaction Quotient
Silver chloride will react with acetic acid to form the complex ion silver acetate. A reaction mixture is prepared by adding 0.25 g of AgCl to a 1.25 L solution that already contains 4.6×10‐6M Ag(CH3COO)(aq), 2.3×10‐3M Cl-, 1.1×10‐8M H+, and 0.010M CH3COOH. Based on this information, which of the statements below is true?
AgCl(s)+CH3COOH(aq)⇌Ag(CH3COO)(aq)+Cl−(aq)+H+(aq)K=5.87×10−16AgCl(s)+CH_3 COOH(aq)⇌Ag(CH_3 COO)(aq)+Cl^- (aq)+H^+ (aq)\qquad K = 5.87×10^{-16}
After allowing this solution to rest for some time:
Equilibrium: Reaction Quotient
Silver chloride will react with acetic acid to form the complex ion silver acetate. A reaction mixture is prepared by adding 0.25 g of AgCl to a 1.25 L solution that already contains 4.6×10‐6M Ag(CH3COO)(aq), 2.3×10‐3M Cl-, 1.1×10‐8M H+, and 0.010M CH3COOH. Based on this information, which of the statements below is true?
AgCl(s)+CH3COOH(aq)⇌Ag(CH3COO)(aq)+Cl−(aq)+H+(aq)K=5.87×10−16AgCl(s)+CH_3 COOH(aq)⇌Ag(CH_3 COO)(aq)+Cl^- (aq)+H^+ (aq)\qquad K = 5.87×10^{-16}
After allowing this solution to rest for some time:
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Practice: Calculating Equilibrium Concentrations
Iodine chloride (ICl) can decompose, forming iodine and chlorine gases. If a reaction vessel is prepared by filling a 5.00 L container with 0.500 mol each of ICl, I2, and Cl2.
2ICl(g)⇌I2(g)+Cl2(g)KC=0.110 (at 25°C)2ICl(g)⇌I_2 (g)+Cl_2 (g)\qquad K_C = 0.110\ (at \ 25°C)
a) In which direction will the reaction proceed (towards products or reactants)? Show how you determined your answer.
Equilibrium constant
Which of the following is not included in an equilibrium equation?
Equilibrium constant
A 1.0 L flask was loaded and the system was allowed to reach equilibrium at 25 °C. The equilibrium mixture was found to contain: 1.5 mol Cr (S), 1.5 mol CCI4 (g), 2.3 mol CrCl3, (g), and 2.5 mol C (S). Determine the Kc value for this reaction at 25 °C.
4Cr(s)+3CCl4(g)⇌4CrCl3(g)+3C(s)ΔH=26.9kJ4Cr(s)+3CCl_4 (g)\rightleftharpoons4CrCl_3 (g)+3C(s)\qquad ΔH = 26.9 kJ
Equilibrium constant: Reaction quotient
Consider the reaction:
A+2B⇌C+DA + 2B ⇌ C + D
At a particular temperature this reaction is reactant-favoured at equilibrium. If for the current concentrations the forward reaction is favoured, which of the following statements is true?
Equilibrium: ICE table
Given the following reaction, if we start with 16moles of CH2=CHCH3(g), 16 moles of NH3(g) and 320moles of O2(g) in a 1L container, what will the equilibrium concentration be for H2O(g)?
CH2=CHCH3(g) + NH3(g) + 32O2(g) ⇌ CH2=CHC≡N(g) + 3H2O(g) K=1.2×1094
For this problem, since the K value is very large, the reaction will go to completion. We will have 1 ICE table for the reaction going to completion and a second ICE table for the reverse reaction where we will find the equilibrium concentrations!
ICE Tables
H2 and I2 are placed in a closed flask such that the concentrations of H2 and I2 are both 0.10 M respectively. The mixture is heated to 400oC and equilibrium is reached. Analysis of the equilibrium mixture finds HI to have a concentration of 0.050 M. Calculate the value of the equilibrium constant,
Kc. H2 (g) + I2 (g) ⇌ 2 HI (g)
Solution:
Concept Clarifier
Consider the following reaction
2 SO2+O2⇌2 SO3\rm 2\ {SO_2} \quad+\quad {O_2}\quad \xrightleftharpoons{\hspace{1.5cm}}\quad 2\ {SO_3}
ΔH0=−180 kJ/mol\Delta H^0=-180\ kJ/mol
Equilibrium constant: Kc
A one liter vessel was filled with 0.398 mol of NOCl(g). Then the temperature of the system was increased to 245 °C to undergo the following reaction:
2NOCl(g)⇌2NO(g)+Cl2(g)2NOCl(g) \rightleftharpoons 2NO(g) +Cl_2(g)
When equilibrium was attained, the concentration of Cl2 was 0.0225 mol/liter. Calculate the value of Kc at 245 °C for the reaction.
Equilibrium constant: Kc
A 1.0 L flask was loaded and the system was allowed to reach equilibrium at 25 °C. The equilibrium mixture was found to contain: 1.5 mol Cr (S), 1.5 mol CCI4 (g), 2.3 mol CrCl3, (g), and 2.5 mol C (S). Determine the Kc value for this reaction at 25 °C.
Equilibrium: ICE Table
Cyclohexane (C6H12) undergoes an isomerization in the presence of the appropriate catalyst to form a compound called MCP.
C6H12 (g) ⇌ MCP (g) Kc = 0.143 at 25oC
The initial concentrations are [C6H12] = 0.200 M and [MCP] = 0.100 M. What are the equilibrium concentrations of these two compounds?
Equilibrium: Magnitude of equilibrium constant
The value of Kc for a particular chemical equilibrium is 1.0x1013. Hence, we can conclude:
Equilibrium constant
Which of the following expression is the correct equilibrium-constant expression for the reaction below?
HF (aq) + H2O (l) ⇌ H3O+ (aq) + F- (aq)
Equilibrium Constant: Kp
Consider the following reaction:
N2O4 (g) ⇌ 2 NO2 (g)
A flask is charged with 6.000 atm of N2O4 (g) and 4.000 atm of NO2 (g) at 25oC. After equilibrium is reached the partial pressure of NO2 is 1.536 atm. Calculate Kp for the reaction.
Equilibrium: Concentration
An equilibrium mixture of CO, O2 and CO2 at a certain temperature contains [CO2] = 0.0010 M and [O2] = 0.0015 M. At this temperature the equilibrium constant Kc = 1.4x102.
2 CO (g) + O2 (g) ⇌ 2 CO2 (g) + heat
What is the equilibrium concentration of CO?
Equilibrium constant
Consider the following reaction of mercury and oxygen:
2 Hg (l) + O2 (g) ⇌ 2 HgO (s)
For this reaction, the equilibrium amounts of reactants and products are: 1.00 g of HgO (s), 2.00 mL of Hg (l), and 1.60 mol/L of O2 (g). What is the value of the equilibrium constant, Kc? (In case you wish to know, HgO (s) has molar mass 217 g/mol and density 1.10 g/mL, and metallic mercury Hg (l) has atomic mass 201 g/mol and density 13.6 g/mL.)
Equilibrium constant
What is the correct expression for the equilibrium constant of the following reaction? 6 CO2 (g) + 6 H2O (g) ⇌ C6H12O6 (s) + 6 O2 (g)
Equilibrium: ICE Table
A reaction mixture consisting of 0.400 mol H2 and 1.60 mol I2 was introduced into a 3.00 L flask and heated. At equilibrium 60% of the hydrogen gas had reacted. What is the equilibrium constant Kc for the reaction H2 (g) + I2 (g) ⇌ 2 HI (g)?
Equilibrium constant: Kp
Consider the equilibrium reaction: 2 NO2 (g) ⇌ N2O4 (g)
A container initially holds a mixture of 2.0 atm of N2O4 and 1.0 atm of NO2. The system is allowed to equilibrate and it is noticed that the pressure of NO2 has increased by 0.3 atm. What is the Kp for this equilibrium?
Equilibrium constant
Which of the following pairs of chemical equation and equilibrium constant expression is/are CORRECT?
1. 4 Bi (s) + 3 O2 (g) ⇌ 2 Bi2O3 (s), K = [O2]3
2. Ba (s) + 2 H+ (aq) ⇌ Ba2+ (aq) + H2 (g), K = [Ba2+][H2] / [H+]
Equilibrium: Equilibrium constant
For the process: PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)
Kc = 0.040 at 450oC. If a reaction is initiated with 0.40 mol of Cl2 and 0.40 mol of PCl3 in a 1.0 liter container, what is the equilibrium concentration of Cl2 in the system?
Equilibrium: Equilibrium constant
For the process: N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
Determine the value of Kc when an equilibrium mixture contains 0.0420 mol N2, 0.516 mol H2, and 0.0357 mol NH3 in a 1.00 liter container at 400oC.
Equilibrium: Equilibrium constant
For the process 2 SO3 (g) ⇌ 2 SO2 (g) + O2 (g), the equilibrium constant expression (Kc) is:
Equilibrium: Equilibrium constant
When 1.00 mol of H2 and 1.00 mol of Br2 are combined in a 1.00 liter flask and heated to 448oC, 0.780 mol of HBr are formed according to the equilibrium process H2 (g) + Br2 (g) ⇌ 2 HBr (g). What is Kc for this process at 448oC?
Equilibrium: Equilibrium Constant
Given the equilibrium information for water below, what is the concentration of hydroxide ions in a solution of 1.5 M HCl?
2 H2O (l) ⇌ H3O+ (aq) + OH- (aq), Kc = 1x10-14 at 20oC
Equilibrium: Equilibrium constant
Given the equilibrium information for water below, what is the concentration of hydroxide ions in water?
2 H2O (l) ⇌ H3O+ (aq) + OH- (aq), Kc = 1x10-14 at 20oC
Equilibrium: Equilibrium constant
For the equilibrium process NH4SH (s) ⇌ NH3 (g) + H2S (g), Kc = 1.2x10-4 at 218oC. What is the equilibrium concentration of NH3 if a sample of NH4SH is allowed to achieve equilibrium at 218oC in a sealed rigid vessel?
Equilibrium: Equilibrium constant
For the equilibrium process 2 NO (g) + Br2 (g) ⇌ 2 NOBr (g), the equilibrium constant expression (Kc) is:
Which equilibrium K expression for the reactions shown below is CORRECT?
For the equilibrium process 2 NO (g) + Br2 (g) ⇌ 2 NOBr (g), the equilibrium constant expression (Kc) is:
Equilibrium constant
The equilibrium constant for the process: AgCl (s) ⇌ Ag+ (aq) + Cl- (aq) is 1.0x10-10. What would be the equilibrium concentration of Ag+ in solution when 10 g of the AgCl salt is added to pure water?
Equilibrium constant
Equal quantities of hydrogen and gaseous iodine at 700 K (427oC) are placed in a reaction vessel and allowed to reach equilibrium according to the following equation:
H2 (g) + I2 (g) ⇌ 2 HI (g)
If the following equilibrium concentrations are measured: [H2] = [I2] = 0.021 mol/L and [HI] = 0.158 mol/L, what is the equilibrium constant for this reaction at 700 K?
Equilibrium: Equilibrium constant
If the equilibrium constant for reaction 1 below is K, what is the equilibrium constant for reaction 2?
(1) SO2 (g) + ½ O2 (g) ⇌ SO3 (g)
(2) 2SO3 (g) ⇌ 2 SO2 (g) + O2 (g)
Equilibrium: Equilibrium constant
If Kc = 0.212 at 100oC for N2O4 (g) ⇌ 2 NO2 (g)
Determine the value of Kc at 100oC for 2 NO2 (g) ⇌ N2O4 (g)
Equilibrium Constant
A 400 L reactor is charged with 10.0 moles of ammonia (NH3) at 450 K. Over time the ammonia decomposes into it's elements according to the reaction below and at equilibrium the pressure of H2 is 0.0140 atm. Calculate the equilibrium constant for this reaction.
2 NH3(g)→3 H2(g)+N2(g)2\ NH_{3(g)}\rightarrow 3\ H_{2(g)}+N_{2(g)}
Equilibrium constant
A reaction is shown below between chlorine gas and iodine gas at 600 K. After the reaction comes to equilibrium the partial pressures are
p(Cl2)=0.438 atm   p(I2)=0.146 atm    p(ICl3(g))=1.767 atmp(Cl_2)=0.438 \ atm\ \ \ p(I_2)=0.146\ atm \ \ \ \ p(ICl_{3(g)})=1.767\ atm
3 Cl2(g)+I2(g)→2 ICl3(g)3\ Cl_{2(g)}+I_{2(g)}\rightarrow 2\ ICl_{3(g)}
For an experiment involving the Haber’ process,
N2(g)+3H2(g)⇋2NH3(g)N_{2(g)}+3H_{2(g)} \leftrightharpoons 2NH_{3(g)}
The initial concentrations were: [N2] = 3.00 M, [H2] = 4.00 M and [NH3] = 1.00 M. After some time, the concentration of H2 was found to be 2.80 M. What was the concentration of NH3 at this time?
If an endothermic equilibrium reaction has a K value of 3.4 at room temperature, which of the following statements is correct?
Consider the following equilibrium:
Br2 (g) + Cl2 (g) ⇌ 2 BrCl (g) at 400 K, Kc = 7.0
If 0.20 M of Br2 (g) and 0.20 M of Cl2 (g) are placed in a vessel and heated to 400 K, what is the equilibrium concentrations of BrCl (g)?
At 450 K, the equilibrium constant in terms of pressure,
CO(g)+H2O(g)→H2(g)+CO2(g)Kp=34.7CH4(g)+O2→CO2(g)+2 H2(g)Kp=119.2\begin{array}{cc} CO_{(g)}+H_2O_{(g)}\rightarrow H_{2(g)}+CO_{2(g)} & K_p=34.7 \\ CH_{4(g)}+O_{2}\rightarrow CO_{2(g)}+2\ H_2{(g)} & K_p=119.2 \end{array}
What is Kp for the following reactio at 450 K?
The equilibrium constant, Kc, for the following reaction below was measured at 7.7.
SO3(g)+NO(g)⇌NO2(g)+SO2(g)SO_{3}(g)+NO(g)\rightleftharpoons NO_{2}(g)+SO_{2}(g)
At the same temperature the measurement was taken, a mixture of 0.4 M SO3 and 0.4 M NO was generated. After allowing the system to reach equilibrium what is the concentration of SO2?
Equilibrium constant
At a certain temperature, the value of the equilibrium constant for the following reaction is
Kc = 100. N2 (g) + 2 O2 (g) ⇌ 2 NO2 (g)
What is the equilibrium constant for the following reaction?
Equilibrium constant
Which of the following substances present in a chemical reaction would NOT normally be included in the equilibrium constant expression?
Equilibrium: ICE Table
Cyclohexane (C6H12) undergoes an isomerization in the presence of the appropriate catalyst to form a compound called MCP.
C6H12 (g) ⇌ MCP (g) Kc = 0.143 at 25oC
The initial concentrations are [C6H12] = 0.800 M and [MCP] = 0.100 M. What are the equilibrium concentrations of these two compounds?
Equilibrium: ICE Table
A mixture of 0.682 mol of H2 and 0.440 mol of Br2 combined in a reaction vessel with a volume of 2.00 L achieves equilibrium at 700 K according to the equation below. At equilibrium, there are 0.556 mol of H2 present. How many moles of Br2 are present at equilibrium?
H2 (g) + Br2 (g) ⇌ 2 HBr (g)
For a specific reaction, which of the following statements about the equilibrium constant is true?
Equilibrium: Equilibrium Constant
For the equilibrium process 2 SO3 (g) ⇌ 2 SO2 (g) + O2 (g), determine the value of Kc when an equilibrium mixture contains 0.025 mol O2, 0.27 mol SO2, and 0.018 mol SO3 in a 5.00 liter container at 220oC.
For the process: N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
Determine the value of Kc when an equilibrium mixture contains 0.0420 mol N2, 0.516 mol H2, and 0.0357 mol NH3 in a 1.00 liter container at 400oC.
Which of the following expression is the correct equilibrium-constant expression for the reaction below?
HF(aq) + H2O(l) ⇌ H3O+(aq) + F-(aq)
1.
For the equilibrium process 2 NO (g) + Br2 (g) ⇌ 2 NOBr (g), the equilibrium constant expression (Kc) is:
Equilibrium Constant
A one liter vessel was filled with 0.398 mol of NOCl(g). Then the temperature of the system was increased to 245 °C to undergo the following reaction:
2NOCl(g)⇌2NO(g)+Cl2(g)2NOCl(g) \rightleftharpoons 2NO(g) +Cl_2(g)
When equilibrium was attained, the concentration of Cl2 was 0.0225 mol/liter. Calculate the value of Kc at 245 °C for the reaction.
Equilibrium
Consider the following equilibria:
2HCl(g)⇌H2(g)+Cl2(g)Kc,12HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2H2S2(g)⇌2H2(g)+S2(g)Kc,22H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
Equilibrium: Equilibrium constant
For the equilibrium process NH4SH (s) ⇌ NH3 (g) + H2S (g), Kc = 1.2x10-4 at 218oC. What is the equilibrium concentration of NH3 if a sample of NH4SH is allowed to achieve equilibrium at 218oC in a sealed rigid vessel?
Equilibrium: Equilibrium Constant
For the equilibrium process 2 SO3 (g) ⇌ 2 SO2 (g) + O2 (g), determine the value of Kc when an equilibrium mixture contains 0.025 mol O2, 0.27 mol SO2, and 0.018 mol SO3 in a 5.00 liter container at 220oC.
Equilibrium constant
A 1.0 L flask was loaded and the system was allowed to reach equilibrium at 25 °C. The equilibrium mixture was found to contain: 1.5 mol Cr (S), 1.5 mol CCI4 (g), 2.3 mol CrCl3, (g), and 2.5 mol C (S). Determine the Kc value for this reaction at 25 °C.
Equilibrium: Magnitude of Equilibrium Constants
The value of KC for the reaction below is 1.2×10‐42 at 500 K.
H2(g)⇌2H(g)H_2 (g)⇌2H(g)
Which of the following statements is true when the reaction is at equilibrium?
Which answer below correctly describes the calculation to find the equilibrium expression K4?
CH4(g)+H2O(g)⇌CO(g)+3H2(g)K1CH4(g)+2S2(g)⇌CS2(g)+2H2S(g)K2CO2(g)+H2(g)⇌CO(g)+H2O(g)K3CS2(g)+2H2S(g)+3CO2(g)⇌4CO(g)+2S2(g)+2H2O(g)K4\def\arraystretch{1.5} \begin{array}{c:c} CH_4 (g)+H_2 O(g)⇌CO(g)+3H_2 (g) & K_1 \\ CH_4 (g)+2S_2 (g)⇌CS_2 (g)+2H_2 S(g) & K_2\\ CO_2 (g)+H_2 (g)⇌CO(g)+H_2 O(g) & K_3\\ CS_2 (g)+2H_2 S(g)+3CO_2 (g)⇌4CO(g)+2S_2 (g)+2H_2 O(g) & K_4 \end{array}
Equilibrium Constant
If 1.00 mole of HCl (g) is placed in an 8.00 L container, what will be the concentration of H2 in that container at equilibrium?
2HCl(g)⇌H2(g)+Cl2(g)KC=1.3×10−92HCl(g)⇌H_2 (g)+Cl_2 (g) \qquad K_C=1.3×10^{-9}
Equilibrium Constant
Carbon disulfide, CS2, and chlorine gas react according to the following equation:
CS2(g)+3Cl2(g)⇌S2Cl2(g)+CCl4(g)CS_2 (g)+3Cl_2 (g)⇌ S_2 Cl_2 (g)+CCl_4 (g)
When 1.00 mol of CS2 and 3.00 mol of Cl2 are placed in a 2.00 L container and allowed to come to equilibrium, the mixture is found to contain 0.250 mol of CCl4. What is the amount of Cl2 at equilibrium?
Equilibrium: Calculating Equilibrium Concentrations
Iodine chloride (ICl) can decompose, forming iodine and chlorine gases. If a reaction vessel is prepared by filling a 5.00 L container with 0.500 mol each of ICl, I2, and Cl2.
2ICl(g)⇌I2(g)+Cl2(g)KC=0.110 (at 25°C)2ICl(g)⇌I_2 (g)+Cl_2 (g)\qquad K_C = 0.110\ (at \ 25°C)
a) In which direction will the reaction proceed (towards products or reactants)? Show how you determined your answer.
Equilibrium Constant
Given the following information:
Ni(OH)2(s)⇌Ni2+(aq)+2OH−(aq)Ksp=6.0×10−16H2O(l)⇌H+(aq)+OH−(aq)Kw=1.0×10−14\def\arraystretch{1.5}\begin {array}{cc}Ni(OH)_2 (s) ⇌Ni^{2+} (aq)+2OH^- (aq)&&K_{sp}= 6.0 ×10^{-16}\\ H_2 O(l) ⇌H^+ (aq)+OH^- (aq) &&K_w= 1.0×10^{-14}\end{array}
What is the equilibrium constant for the reaction,
Equilibrium: Equilibrium constant
At 25 ˚C, KP = 5.2 × 10–2 for the following decomposition reaction:
NH4HS(s)⇌NH3(g)+H2S(g)NH_4HS(s)⇌NH_3(g)+H_2S(g)
Given the following information at 298 K:
SnO2(s)+2H2(g)⇌Sn(s)+2H2O(g)K1=8.12H2(g)+CO2(g)⇌H2O(g)+CO(g)K2=0.771\def\arraystretch{1.5} \begin{array}{cc} SnO_2 (s) + 2 H_2 (g) ⇌ Sn (s) + 2 H_2 O (g) & K_1 = 8.12 \\ H_2 (g) + CO_2 (g) ⇌ H_2 O (g) + CO (g) &K_2 = 0.771 \end{array}
Determine the K for the overall reaction: SnO2(s)+2CO(g)⇌Sn(s)+2CO2(g).SnO_2 (s) + 2 CO (g) ⇌ Sn (s) + 2 CO_2 (g).
Chemical Equilibria
Consider this balanced chemical reaction and the molecular representation for both of the next two questions: 2AB(g)⇌A2(g)+B2(g)2AB(g)⇌A_2(g)+B_2(g)
The following equilibrium concentrations were observed in the synthesis of NH3 at
127oC:[NH3]=3.1×10−2M;[N2]=8.5×10−1M;[H2]=3.1×10−3M127^oC:[NH_3]=3.1\times 10^{-2} M; [N_2]=8.5\times 10^{-1} M; [H_2]=3.1\times 10^{-3}M
The balanced reaction is: N2 + 3H2 -eqm> NH3
Which of the graphs below could correctly illustrate the outcome of the reaction?
2BrCl⇌Cl2+Br22BrCl \rightleftharpoons Cl_2+Br_2 Kc=5.0K_c=5.0
Equilibrium: ICE Table
A sample of 0.0015 moles of F2 was sealed into a 1.0 L reaction vessel and heated to 1000. K to study the dissociation into F atoms:
F2⇌2F        Kc=1.2×10−4F_2 \rightleftharpoons 2F\ \ \ \ \ \ \ \ K_c=1.2\times 10^{-4}
What are [F2] and [F] at equilibrium?
Equilibrium: Reaction Quotient
Silver chloride will react with acetic acid to form the complex ion silver acetate. A reaction mixture is prepared by adding 0.25 g of AgCl to a 1.25 L solution that already contains 4.6×10‐6M Ag(CH3COO)(aq), 2.3×10‐3M Cl-, 1.1×10‐8M H+, and 0.010M CH3COOH. Based on this information, which of the statements below is true?
AgCl(s)+CH3COOH(aq)⇌Ag(CH3COO)(aq)+Cl−(aq)+H+(aq)K=5.87×10−16AgCl(s)+CH_3 COOH(aq)⇌Ag(CH_3 COO)(aq)+Cl^- (aq)+H^+ (aq)\qquad K = 5.87×10^{-16}
After allowing this solution to rest for some time:
The reaction for the reforming of methane from steam is given by:
CH4(g)+H2O(g)⇌CO(g)+3H2(g)CH_4(g)+H_2O(g)⇌CO(g)+3H_2(g)
A closed reaction vessel starts with initial concentrations of 1.00 M for every gas. After reaching equilibrium at a particular temperature, the final CO concentration was measured to be 0.80 M. Determine KC for this reaction at this temperature.