Q466-05 Consider
the following reaction in the Contact Process for the production of sulfuric
acid:
2SO2(g) + O2(g)
2SO3(g) |
Temperature /K
|
Equilibrium constant Kc /dm3 mol-1 |
298
|
9.77 x 1025 |
500
|
8.61 x 1011 |
700 |
1.75 x 106 |
The value of ΔG for the reaction is -140 kJ at 298 K. What
can be deduced by the sign of ΔG
show
|
The reaction is spontaneous under standard conditions. |
|
The values of ΔH
and ΔS for the
reaction at 298K are ΔH=
-196 kJ and ΔS
= -188 JK-1. State and explain what will happen to the spontaneity
of the reaction is the temperature of the reaction is increased.
show
|
As the entropy term is negative, the second part of the Gibbs
free energy relationship, (-TΔS), becomes positive. The
higher the temperature the more positive the term. Hence, a
temperature will be reached at which the magnitude of the second
term is larger than that of the enthalpy term. At this temperature
the reaction becomes non-spontaneous. |
|
Study
question 1 Study
question 2 Study
question 3 Study
question 4