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# Determining temperature change with equilibrium

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For the equilibrium system
CO2(g) + H2(g) CO(g) + H2O(g) H = +42 kJ/mol
K equals 1.6 at 1260 K. If 0.15 mol each of CO2, H2, CO, and H2O (all at 1260 K) were placed in a 1.0-L thermally insulated vessel that was also at 1260 K, then when the system came to equilibrium,

A)
the temperature would remain constant and the mass of CO2 would increase.
B)
the temperature would decrease and the mass of CO2 would decrease.
C)
the temperature would increase and the mass of CO2 would decrease.
D)
the temperature would decrease and the mass of CO2 would increase.
E)
the temperature would increase and the mass of CO2 would increase.

https://brainmass.com/chemistry/energetics-and-thermodynamics/determining-temperature-change-with-equilibrium-389143

#### Solution Preview

It is useful to start by looking at the equilibrium expression for the reaction

K=[CO][H2O]/[CO2][H2]

Since K=1.6, then the products must be more in terms of moles than reactants, since ...

#### Solution Summary

In this solution the problem of deducing what will happen to the temperature of a system is considered. In this case, we are adding components that will react and form an equilibrium, and we want to know how far the reaction will proceed, and what will happen to the temperature? A full explanation of this equilibrium problem is included.

Updated January 13, 2011 to correct a small error

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## Chemistry: Chemical Equilibrium

Chemical Equilibrium

1- Determine the value of the equilibrium constant, K goal , for the reaction
N 2 (g)+H 2 O(g)⇌NO(g)+ 1 2 N 2 H 4 (g) , K goal =?
by making use of the following information:
1.N 2 (g)+O 2 (g)⇌2NO(g) ,
K 1 =
4.10×10 −31

2.N 2 (g)+2H 2 (g)⇌N 2 H 4 (g) ,
K 2 =
7.40×10 −26

3.2H 2 O(g)⇌2H 2 (g)+O 2 (g) ,
K 3 =
1.06×10 −10

2- Determine the equilibrium constant, K goal , for the reaction
4PCl 5 (g)⇌P 4 (s)+10Cl 2 (g), K goal =?
by making use of the following information:
1. P 4 (s)+6Cl 2 (g)⇌4PCl 3 (g), K 1 =2.00×10 19
2. PCl 5 (g)⇌PCl 3 (g)+Cl 2 (g), K 2 =1.13×10 −2
3- For the reaction 2A(g)+2B(g)⇌C(g)
K c = 89.2 at a temperature of 303 ∘ C .
Calculate the value of K p .

4- For the reaction X(g)+3Y(g)⇌2Z(g)
K p = 1.35×10−2 at a temperature of 265 ∘ C
Calculate the value of K c .

5- Why are pure solids and pure liquids not included in a Kc expression? Choose from:
Pure solids and pure liquids are not reactive enough to be included in an equilibrium expression.
Pure solids and pure liquids do not participate in reversible (equilibrium) reactions.
Pure solids and pure liquids do not change in volume over the course of a reaction.
The concentrations of pure solids and pure liquids do not change during reactions.

6- Part A :Phosgene (carbonyl chloride), COCl 2 , is an extremely toxic gas that is used in manufacturing certain dyes and plastics. Phosgene can be produced by reacting carbon monoxide and chlorine gas at high temperatures:
CO(g)+Cl 2 (g)⇌COCl 2 (g)
Carbon monoxide and chlorine gas are allowed to react in a sealed vessel at 465 ∘ C . At equilibrium, the concentrations were measured and the following results obtained:
Gas Partial Pressure
(atm )

CO
0.740
Cl 2
1.14
COCl 2
0.150
What is the equilibrium constant, K p , of this reaction?

7- In Part A, you were given the equilibrium pressures, which could be plugged directly into the formula for K . In Part B however, you will be given initial concentrations and only one equilibrium concentration. You must use this data to find all three equilibrium concentrations before you can apply the formula for K .
Part B
The following reaction was performed in a sealed vessel at 783 ∘ C :
H 2 (g)+I 2 (g)⇌2HI(g)
Initially, only H 2 and I 2 were present at concentrations of [H 2 ]=3.20M and [I 2 ]=2.00M .The equilibrium concentration of I 2is 0.0700M . What is the equilibrium constant, K c , for the reaction at this temperature?