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Equilibrium Constant
Related Topics
Wize University Chemistry Textbook > Equilibrium
Solving for K in Different Scenarios
2 Activities
Based on the reactions and equilibrium constants given below, determine the value of the equilibrium constant (K
f
) for the formation of the soluble PbI
4
2-
complex:
𝑃
𝑏
𝐼
2
(
𝑠
)
⇌
𝑃
𝑏
2
+
(
𝑎
𝑞
)
+
2
𝐼
−
(
𝑎
𝑞
)
𝐾
𝑠
𝑝
=
7.9
×
10
−
9
𝑃
𝑏
𝐼
2
(
𝑠
)
+
2
𝐼
−
(
𝑎
𝑞
)
⇌
𝑃
𝑏
𝐼
4
2
−
(
𝑎
𝑞
)
𝐾
=
2.37
×
10
−
4
𝑃
𝑏
2
+
(
𝑎
𝑞
)
+
4
𝐼
−
(
𝑎
𝑞
)
⇌
𝑃
𝑏
𝐼
4
2
−
(
𝑎
𝑞
)
𝐾
𝑓
=
?
\begin{alignedat}{} &𝑃𝑏𝐼_2 (𝑠) ⇌𝑃𝑏^{2+}(𝑎𝑞)+2 𝐼^− (𝑎𝑞) &&𝐾_{𝑠𝑝}=7.9×10^{−9}\\ &𝑃𝑏𝐼_2(𝑠)+2 𝐼^− (𝑎𝑞) ⇌𝑃𝑏𝐼_4^{2−} (𝑎𝑞) &&𝐾=2.37×10^{−4}\\ &𝑃𝑏^{2+} (𝑎𝑞)+4 𝐼^− (𝑎𝑞)⇌𝑃𝑏𝐼_4^{2−} (𝑎𝑞) &&𝐾_𝑓= ? \end{alignedat}
P
b
I
2
(
s
)
⇌
P
b
2
+
(
a
q
)
+
2
I
−
(
a
q
)
P
b
I
2
(
s
)
+
2
I
−
(
a
q
)
⇌
P
b
I
4
2
−
(
a
q
)
P
b
2
+
(
a
q
)
+
4
I
−
(
a
q
)
⇌
P
b
I
4
2
−
(
a
q
)
K
s
p
=
7.9
×
1
0
−
9
K
=
2.37
×
1
0
−
4
K
f
=
?
3.0×10
4
3.3×10
-5
1.9×10
-12
1.4×10
-1
I don't know
Check Submission
More Solving for K in Different Scenarios Questions:
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Concept Clarifier
Consider the following reaction
2
S
O
2
+
O
2
⇌
2
S
O
3
\rm 2\ {SO_2} \quad+\quad {O_2}\quad \xrightleftharpoons{\hspace{1.5cm}}\quad 2\ {SO_3}
2
S
O
2
+
O
2
2
S
O
3
Δ
H
0
=
−
180
k
J
/
m
o
l
\Delta H^0=-180\ kJ/mol
Δ
H
0
=
−
180
k
J
/
m
o
l
Equilibrium constant
The value of Kp for the reaction: NO (g)
⇌
½ N
2
(g) + ½ O2 (g) is 2.5x10
7
. What is the K
p
for the reaction: N
2
(g) + O
2
(g)
⇌
2 NO (g)?
Equilibrium constant
The equilibrium constant for reaction #1 below is K. The equilibrium constant for reaction #2 is therefore ________.
(1) 2 SO
3
(g)
⇌
2 SO
2
(g) + O
2
(g)
(2) SO
2
(g) + ½ O
2
(g)
⇌
SO
3
(g)
Equilibrium constant
Consider the following equilibrium: 2 HI (g)
⇌
H
2
(g) + I
2
(g)
If the equilibrium constant for this reaction at a certain temperature is K
c
= 0.04, what is the equilibrium constant K’c for the following reaction at the same temperature:
½ H
2
(g) + ½ I
2
(g) = HI (g)
Equilibrium constant
For the following equilibria determine whether
K
>
1
K > 1
K
>
1
,
K
<
1
K < 1
K
<
1
or
K
≈
1
K \approx 1
K
≈
1
. Enter your answers as "Greater", "Less", "1" respectively.
A)
B)
Equilibrium: Equilibrium constant
If the equilibrium constant for reaction 1 below is K, what is the equilibrium constant for reaction 2?
(1) SO
2
(g) + ½ O
2
(g) ⇌ SO
3
(g)
(2) 2SO
3
(g)
⇌
2 SO
2
(g) + O
2
(g)
Equilibrium: Equilibrium constant
If K
c
= 0.212 at 100
o
C for N
2
O
4
(g)
⇌
2 NO
2
(g)
Determine the value of K
c
at 100
o
C for 2 NO
2
(g)
⇌
N
2
O
4
(g)
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_{2(g)} \hspace{20pt} K_{c,1}
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_{c,2}
2
H
2
S
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
A reaction is found to have an equilibrium constant of 3.5 x 10
-3
at standard temperature. If the enthalpy change of this process is +45.6 kJ/mol, what will be the value of the equilibrium constant at 455 K?
At 450 K, the equilibrium constant in terms of pressure,
C
O
(
g
)
+
H
2
O
(
g
)
→
H
2
(
g
)
+
C
O
2
(
g
)
K
p
=
34.7
C
H
4
(
g
)
+
O
2
→
C
O
2
(
g
)
+
2
H
2
(
g
)
K
p
=
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}
C
O
(
g
)
+
H
2
O
(
g
)
→
H
2
(
g
)
+
C
O
2
(
g
)
C
H
4
(
g
)
+
O
2
→
C
O
2
(
g
)
+
2
H
2
(
g
)
K
p
=
34.7
K
p
=
119.2
What is K
p
for the following reactio at 450 K?
The equilibrium constant, Kc, for the following reaction below was measured at 7.7.
S
O
3
(
g
)
+
N
O
(
g
)
⇌
N
O
2
(
g
)
+
S
O
2
(
g
)
SO_{3}(g)+NO(g)\rightleftharpoons NO_{2}(g)+SO_{2}(g)
S
O
3
(
g
)
+
N
O
(
g
)
⇌
N
O
2
(
g
)
+
S
O
2
(
g
)
At the same temperature the measurement was taken, a mixture of 0.4 M SO
3
and 0.4 M NO was generated. After allowing the system to reach equilibrium what is the concentration of SO
2
?
Equilibrium constant
At a certain temperature, the value of the equilibrium constant for the following reaction is
Kc = 100. N
2
(g) + 2 O
2
(g)
⇌
2 NO
2
(g)
What is the equilibrium constant for the following reaction?
Equilibrium: ICE Table
Cyclohexane (C
6
H
12
) undergoes an isomerization in the presence of the appropriate catalyst to form a compound called MCP.
C
6
H
12
(g)
⇌
MCP (g) K
c
= 0.143 at 25
o
C
The initial concentrations are [C
6
H
12
] = 0.800 M and [MCP] = 0.100 M. What are the equilibrium concentrations of these two compounds?
Equilibrium: Equilibrium Constant
For the equilibrium process 2 SO
3
(g)
⇌
2 SO
2
(g) + O
2
(g), determine the value of K
c
when an equilibrium mixture contains 0.025 mol O
2
, 0.27 mol SO
2
, and 0.018 mol SO
3
in a 5.00 liter container at 220
o
C.
A reaction mixture consisting of 0.400 mol H
2
and 1.60 mol I
2
was introduced into a 3.00 L flask and heated. At equilibrium 60% of the hydrogen gas had reacted. What is the equilibrium constant K
c
for the reaction H
2
(g) + I
2
(g) ⇌ 2 HI (g)?
If the equilibrium constant for reaction 1 below is K, what is the equilibrium constant for reaction 2?
1. SO
2(g)
+ ½ O
2(g)
⇌ SO
3(g)
2. 2 SO
3(g)
⇌ 2 SO
2(g)
+ O
2(g)
If K
c
= 0.212 at 100
o
C for N
2
O
4(g)
⇌ 2 NO
2(g)
Determine the value of K
c
at 100
o
C for 2 NO
2(g)
⇌ N
2
O
4(g)
Equilibrium constant
At 550
o
C acetic acid (CH
3
COOH) is a gas. A sample of pure acetic acid vapour at 550
o
C decomposes into carbon dioxide (CO
2
) and methane (CH
4
) with an equilibrium constant of 3.40 X 10
4
measured in kPa. At equilibrium a near-IR spectrometer meassures the methane partial pressure to be 255 kPa. What are the equilibrium partial pressures for carbon dioxide and acetic acid?
Express your answer in units of kPa to three significant figures. do not include units in the answer field
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:
2
N
O
C
l
(
g
)
⇌
2
N
O
(
g
)
+
C
l
2
(
g
)
2NOCl(g) \rightleftharpoons 2NO(g) +Cl_2(g)
2
N
O
C
l
(
g
)
⇌
2
N
O
(
g
)
+
C
l
2
(
g
)
When equilibrium was attained, the concentration of Cl
2
was 0.0225 mol/liter. Calculate the value of K
c
at 245 °C for the reaction.
Equilibrium
Consider the following equilibria:
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2HCl_{(g)} \rightleftharpoons H_{2(g)} +Cl_2{(g)} \hspace{20pt} K_c,1
2
H
C
l
(
g
)
⇌
H
2
(
g
)
+
C
l
2
(
g
)
K
c
,
1
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
2H_2S_2{(g)} \rightleftharpoons 2H_{2(g)} +S_2{(g)} \hspace{20pt} K_c,2
2
H
2
S
2
(
g
)
⇌
2
H
2
(
g
)
+
S
2
(
g
)
K
c
,
2
Equilibrium: Equilibrium constant
For the equilibrium process NH
4
SH (s) ⇌ NH
3
(g) + H
2
S (g), K
c
= 1.2x10
-4
at 218
o
C. What is the equilibrium concentration of NH
3
if a sample of NH
4
SH is allowed to achieve equilibrium at 218
o
C in a sealed rigid vessel?
Equilibrium: Equilibrium Constant
For the equilibrium process 2 SO
3
(g) ⇌ 2 SO
2
(g) + O
2
(g), determine the value of Kc when an equilibrium mixture contains 0.025 mol O
2
, 0.27 mol SO
2
, and 0.018 mol SO
3
in a 5.00 liter container at 220
o
C.
Equilibrium: Equilibrium Constant
If Kc = 0.212 at 100
o
C for N
2
O
4
(g) ⇌ 2 NO
2
(g)
Determine the value of K
c
at 100
o
C for 2 NO
2
(g)
⇌
N
2
O
4
(g)
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 CCI
4
(g), 2.3 mol CrCl
3
, (g), and 2.5 mol C (S). Determine the K
c
value for this reaction at 25 °C.
Which answer below correctly describes the calculation to find the equilibrium expression K
4
?
C
H
4
(
g
)
+
H
2
O
(
g
)
⇌
C
O
(
g
)
+
3
H
2
(
g
)
K
1
C
H
4
(
g
)
+
2
S
2
(
g
)
⇌
C
S
2
(
g
)
+
2
H
2
S
(
g
)
K
2
C
O
2
(
g
)
+
H
2
(
g
)
⇌
C
O
(
g
)
+
H
2
O
(
g
)
K
3
C
S
2
(
g
)
+
2
H
2
S
(
g
)
+
3
C
O
2
(
g
)
⇌
4
C
O
(
g
)
+
2
S
2
(
g
)
+
2
H
2
O
(
g
)
K
4
\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}
C
H
4
(
g
)
+
H
2
O
(
g
)
⇌
C
O
(
g
)
+
3
H
2
(
g
)
C
H
4
(
g
)
+
2
S
2
(
g
)
⇌
C
S
2
(
g
)
+
2
H
2
S
(
g
)
C
O
2
(
g
)
+
H
2
(
g
)
⇌
C
O
(
g
)
+
H
2
O
(
g
)
C
S
2
(
g
)
+
2
H
2
S
(
g
)
+
3
C
O
2
(
g
)
⇌
4
C
O
(
g
)
+
2
S
2
(
g
)
+
2
H
2
O
(
g
)
K
1
K
2
K
3
K
4
Equilibrium Constant
Given the following information:
N
i
(
O
H
)
2
(
s
)
⇌
N
i
2
+
(
a
q
)
+
2
O
H
−
(
a
q
)
K
s
p
=
6.0
×
10
−
16
H
2
O
(
l
)
⇌
H
+
(
a
q
)
+
O
H
−
(
a
q
)
K
w
=
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}
N
i
(
O
H
)
2
(
s
)
⇌
N
i
2
+
(
a
q
)
+
2
O
H
−
(
a
q
)
H
2
O
(
l
)
⇌
H
+
(
a
q
)
+
O
H
−
(
a
q
)
K
s
p
=
6.0
×
1
0
−
16
K
w
=
1.0
×
1
0
−
14
What is the equilibrium constant for the reaction,
Equilibrium: Equilibrium constant
At 25 ˚C, K
P
= 5.2 × 10
–2
for the following decomposition reaction:
N
H
4
H
S
(
s
)
⇌
N
H
3
(
g
)
+
H
2
S
(
g
)
NH_4HS(s)⇌NH_3(g)+H_2S(g)
N
H
4
H
S
(
s
)
⇌
N
H
3
(
g
)
+
H
2
S
(
g
)
Use the following scenario for the next two questions
The reaction for the reforming of methane from steam is given by:
C
H
4
(
g
)
+
H
2
O
(
g
)
⇌
C
O
(
g
)
+
3
H
2
(
g
)
CH_4 (g) + H_2 O (g) ⇌ CO (g) + 3 H_2 (g)
C
H
4
(
g
)
+
H
2
O
(
g
)
⇌
C
O
(
g
)
+
3
H
2
(
g
)
Given the following information at 298 K:
S
n
O
2
(
s
)
+
2
H
2
(
g
)
⇌
S
n
(
s
)
+
2
H
2
O
(
g
)
K
1
=
8.12
H
2
(
g
)
+
C
O
2
(
g
)
⇌
H
2
O
(
g
)
+
C
O
(
g
)
K
2
=
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}
S
n
O
2
(
s
)
+
2
H
2
(
g
)
⇌
S
n
(
s
)
+
2
H
2
O
(
g
)
H
2
(
g
)
+
C
O
2
(
g
)
⇌
H
2
O
(
g
)
+
C
O
(
g
)
K
1
=
8.12
K
2
=
0.771
Determine the
K
for the overall reaction:
S
n
O
2
(
s
)
+
2
C
O
(
g
)
⇌
S
n
(
s
)
+
2
C
O
2
(
g
)
.
SnO_2 (s) + 2 CO (g) ⇌ Sn (s) + 2 CO_2 (g).
S
n
O
2
(
s
)
+
2
C
O
(
g
)
⇌
S
n
(
s
)
+
2
C
O
2
(
g
)
.
Equilibrium and Le Chatelier's Principle
At time = t
0
, 0.40 mol of Br
2
(ℓ) and 0.40 mol of Cℓ
2
(g) are placed in an empty, rigid 10.00 L flask and allowed to reach equilibrium.
After reaching equilibrium at time = t
2
, the flask is found to contain 0.20 mol of BrCℓ (g). The temperature is held constant throughout the reaction.
Equilibrium: Keq Values
Consider the following equilibria:
2
H
B
r
(
g
)
⇌
H
2
(
g
)
+
B
r
(
g
)
K
c
,
1
2HBr_{(g)} \rightleftharpoons H_{2(g)} +Br_{(g)} \hspace{20pt} K_c,_1
2
H
B
r
(
g
)
⇌
H
2
(
g
)
+
B
r
(
g
)
K
c
,
1
2
H
2
O
(
g
)
⇌
2
H
2
(
g
)
+
O
(
g
)
K
c
,
2
2H_2O_{(g)} \rightleftharpoons 2H_{2(g)} +O_{(g)} \hspace{20pt} K_c,_2
2
H
2
O
(
g
)
⇌
2
H
2
(
g
)
+
O
(
g
)
K
c
,
2