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Equilibrium: Magnitude of equilibrium constant

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Wize University Chemistry Textbook > Equilibrium

Q (Reaction Quotient)

4 Activities

Wize University Chemistry Textbook > Equilibrium

The Equilibrium Constant (K)

4 Activities

The value of Kc for a particular chemical equilibrium is 1.0x1013. Hence, we can conclude:
More Q (Reaction Quotient) Questions:
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: 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?
The system: H2(g)+X2(g)⇌2HX(g)H_2(g) + X_2(g) \rightleftharpoons 2 HX(g) has a value of 24.4 for K. A system being studied in a 3.00 liter reactor was charged with 0.150 moles of H2, 0.150 moles of X2, and 0.600 moles of HX. A catalyst was introduced using a remote unit. Which statement below describes the situation?
Express the reaction quotient for the following equilibria in terms of partial pressures and concentration.
2 H2O(l)⇌2 H2(g)+O2(g)\rm 2\ H_2O_{(l)} \quad\xrightleftharpoons{\hspace{1.5cm}}\quad 2\ H_{2(g)}\quad+\quad O_{2(g)}
Express the reaction quotient for the following equilibria in terms of partial pressures and concentration.
 CH4(g)+2 O2(g)⇌CO2(g)+2 H2O(g)\rm \ {CH_{4(g)}} \quad+\quad 2\ {O_{2(g)}}\quad \xrightleftharpoons{\hspace{1.5cm}}\quad {CO_{2(g)}}\quad+\quad 2\ H_2O_{(g)}
At 425 °C, Kp = 4.18 x 10-9 for the reaction:
2HBr(g)↔H2(g)+Br2(g)2HBr_{(g)}\leftrightarrow H_{2(g)}+Br_{2(g)}
In one experiment 0.20 atm of HBr, 0.100 atm of H2 and 0.010 atm of Br2 are placed in a container. Is the reaction at equilibrium? If not, in which direction will it proceed?
At 425 °C, Kp = 4.18 x 10-9 for the reaction:
2HBr(g)↔H2(g)+Br2(g)2HBr_{(g)}\leftrightarrow H_{2(g)}+Br_{2(g)}
In one experiment 0.20 atm of HBr, 0.100 atm of H2 and 0.010 atm of Br2 are placed in a container. Is the reaction at equilibrium? If not, in which direction will it proceed?
Which of the following statements regarding the reaction quotient Qc and the equilibrium constant Kc is true?
Consider the reaction of nitrogen and oxygen gases to produce nitric oxide:
N2(g)+O2(g)⇌2NO(g)                   Kc=4.0×10−4  at  1750 oCN_2(g)+O_2(g) \rightleftharpoons 2NO(g)\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ K_c=4.0\times 10^{-4}\ \ at\ \ 1750 \ ^oC
What is the value of Kp for this reaction at 1750 °C?
At 425 °C, Kp = 4.18 x 10-9 for the reaction:
2HBr(g)↔H2(g)+Br2(g)2HBr_{(g)}\leftrightarrow H_{2(g)}+Br_{2(g)}
In one experiment 0.20 atm of HBr, 0.100 atm of H2 and 0.010 atm of Br2 are placed in a container. Is the reaction at equilibrium? If not, in which direction will it proceed?
Equilibrium: Reaction quotient
The system: H2(g) + X2(g) : 2 HX(g) has a value of 24.4 for Kc. A system being studied in a 3.00 liter reactor was charged with 0.150 moles of H2, 0.150 moles of X2, and 0.600 moles of HX. A catalyst was introduced using a remote unit. Which statement below describes the situation
Consider the following reaction to answer the next two questions:
4Cr(s)+3CCl4(g)⇄4CrCl3(g)+3C(s)        ΔH=26.9kJ4Cr(s)+3CCl_4(g) \rightleftarrows 4CrCl_3(g) +3C(s)\ \ \ \ \ \ \ \ \Delta H=26.9kJ
Equilibrium: Reaction quotient
Consider the following reaction:
4 HCl (g) + O2 (g) ⇌ 2 Cl2 (g) + 2 H2O (g) Kc = 0.063 at 400 K
If the reaction quotient, Q, is 0.100, which of the following statements is FALSE?
Equilibrium: Reaction quotient
The equilibrium constant expressed in terms of partial pressure for the water gas reaction (shown) is Kp = 2.6 at a temperature of 1000 K. C (s) + H2O (g) ⇌ CO (g) + H2 (g)
A closed vessel initially has a sample of solid carbon (graphite), and P(H2O(g)) = 0.600 atm and
P(CO(g)) = 1.525 atm and P(H2(g)) = 0.804 atm. Which one of the following statements is TRUE?
Equilibrium: Reaction quotient
The Kc for the Haber process N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) is 9.60 at 573 K. When 1.0x10-3 moles of ammonia is mixed in a 1 L flask at 573 K with 1.0x10-2 moles of hydrogen and 5.0x10-1 moles of nitrogen, one can conclude that:
Equilibrium: Reaction quotient
Which statement is CORRECT for a reaction that has Kc = 2.43x10-12?
Equilibrium: Reaction quotient
Sulfuryl dichloride (SO2Cl2) can be prepared by the following two-step reaction sequence.
H2S (g) + 1.5 O2 (g) ⇌ SO2 (g) + H2O (g)
SO2 (g) + Cl2 (g) ⇌ SO2Cl2 (g)
Equilibrium: Reaction quotient
For the equilibrium process N2O4 (g) ⇌ 2 NO2 (g), Kc = 0.212 at 100oC. If a reaction is initiated with 0.70 mol of N2O4 and 0.35 mol of NO2 in a 1.0 liter container that is heated to 100oC. At equilibrium, how will the amounts of N2O4 and NO2 compare with the initial amounts?
In a large vessel the following reaction is taking place, PCl5(g)⇌PCl3(g)+Cl2(g)PCl_5\left(g\right)\rightleftharpoons PCl_3\left(g\right)+Cl_2\left(g\right) , Kc=4.18×10−2 at 225°CK_c=4.18 \times 10^{-2}\ at\ 225\degree C . I
A lab partner fills an identical vessel with these gases such that the initial concentrations are [PCl5]=0M, [PCl3]=7.2M, and [Cl2]=2.35M Which of the following statement is TRUE?
Does any solid Cu(OH)2 (Ksp =1.6 x 10-19) form when 0.075g of KOH dissolves in 1.0 L of 1 x 10-3 M Cu(NO3)2
Equilibrium: Reaction quotient
Consider the following hypothetical gas-phase reaction: A (g) ⇌ B (g) Kp = 3.40 at 25oC
If a flask initially contains 1.00 atm of each gas, in what direction will the reaction shift in order to reach equilibrium?
Carbon monoxide and chlorine combine in an equilibrium reaction to produce the highly toxic product, phosgene (COCl2)
CO(g)+Cl2(g)⇌COCl2(g)CO_{(g)} +Cl_{2(g)} \rightleftharpoons COCl_{2(g)}
If the equilibrium constant for this reaction is Kc = 248, predict, if possible, what will happen when the reactants and product are combined with the concentrations shown below:
The graph below shows the concentration of reactants and products for an unknown chemical reaction.
Which of the following statements are correct
i. Q < K at point A
For the reaction N2H4(g) ⇌ N2(g) + 2 H2(g), Kc = 0.026 at 200 K. If we place 2.0 M of N2H4(g), 0.80 M of H2(g), and 3.5 M of N2(g) in a closed vessel, in which way will the reaction proceed to reach equilibrium?
A graduate student sets up an equilibrium demonstration by placing NO2 and N2O4 in flask. These species are in equilibrium with eachother as shown below. Initially the reaction quotient, Q is equal to 3.5, we know that for this reaction K = 1.1 We would predict that,
2 NO2(g)⇌N2O4(g)2\ NO_{2(g)}\rightleftharpoons N_2O_{4(g)}
Equilibrium: Reaction quotient
The system: H2(g) + X2(g) : 2 HX(g) has a value of 24.4 for Kc. A system being studied in a 3.00 liter reactor was charged with 0.150 moles of H2, 0.150 moles of X2, and 0.600 moles of HX. A catalyst was introduced using a remote unit. Which statement below describes the situation
Consider the following reaction to answer the next two questions:
4Cr(s)+3CCl4(g)⇄4CrCl3(g)+3C(s)        ΔH=26.9kJ4Cr(s)+3CCl_4(g) \rightleftarrows 4CrCl_3(g) +3C(s)\ \ \ \ \ \ \ \ \Delta H=26.9kJ
Which of the following statements regarding the reaction quotient Qc and the equilibrium constant Kc is true?
Equilibrium: Reaction quotient
For the equilibrium process N2O4 (g) ⇌ 2 NO2 (g), Kc = 0.212 at 100oC. If a reaction is initiated with 0.70 mol of N2O4 and 0.35 mol of NO2 in a 1.0 liter container that is heated to 100oC. At equilibrium, how will the amounts of N2O4 and NO2 compare with the initial amounts?
Equilibrium: Reaction quotient
A reaction vessel is prepared by putting 0.2 mol of H2S (g) and 0.05 mol of NH3 (g) into a sealed 1.0 L vessel containing 0.05 mol of ammonium hydrosulfide. Based on the reaction given below, will there be a change in the amounts of ammonium hydrosulfide in the flask after waiting for some time?
𝑁𝐻4𝐻𝑆(𝑠)⇌𝐻2𝑆(𝑔)+𝑁𝐻3(𝑔)𝐾𝐶=0.11𝑁𝐻_4𝐻𝑆 (𝑠) ⇌𝐻_2𝑆 (𝑔)+𝑁𝐻_3 (𝑔) \qquad𝐾_𝐶=0.11
Equilibrium: Using The 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 4.6×10‐6 M Ag(CH3COO)(aq), 2.3×10‐3 M Cl-, 1.1×10‐8 M H+, and 0.010 M 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: 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.
Use the following scenario for the next two questions
The reaction for the reforming of methane from steam is given by:
CH4(g)+H2O(g)⇌CO(g)+3H2(g)CH_4 (g) + H_2 O (g) ⇌ CO (g) + 3 H_2 (g)
Consider the reaction: A+2B⇌C+DA+2B\rightleftharpoons 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?
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)
For the following isomerization reaction between butane and isobutane, which statement best describes the system at time 2?
Equilibrium: Reaction Quotient
At 425 °C, Kp = 4.18 x 10-9 for the reaction:
2HBr(g)↔H2(g)+Br2(g)2HBr_{(g)}\leftrightarrow H_{2(g)}+Br_{2(g)}
In one experiment 0.20 atm of HBr, 0.100 atm of H2 and 0.010 atm of Br2 are placed in a container. Is the reaction at equilibrium? If not, in which direction will it proceed?
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 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).
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}
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.