For a particular reaction H = -32 kJ and S = -98 J/K.
a.At what temp will the reaction be at equilibrium?
b.If the temperature is increased from the equilibrium temperature what will happen?
In the freenergy equation
G=H+TS set G=0, solve for Temp
If Temp is increased, G goes more negative, so the reaction goes to completion.
To answer these questions, we need to use the equation for Gibbs free energy (ΔG) and the relationship between ΔG, ΔH, and ΔS.
a. To find the temperature at which the reaction will be at equilibrium, we can use the equation:
ΔG = ΔH - TΔS
At equilibrium, ΔG = 0. Therefore, we can set the equation to zero and solve for T:
0 = -32 kJ - T(-98 J/K)
To convert kJ to J, we multiply by 1000: 0 = -32000 J - T(-98 J/K)
Simplifying: 0 = -32000 J + 98 T J/K
Rearranging the equation: T = 32000 J / 98 J/K
Calculating: T ≈ 326.5 K
Therefore, at approximately 326.5 K, the reaction will be at equilibrium.
b. If the temperature is increased from the equilibrium temperature, the value of T in the equation will be greater than 326.5 K. When T increases, the term -TΔS becomes more negative. As a result, the value of ΔG (Gibbs free energy) will become negative. This means that the reaction will shift towards the products, away from equilibrium, in order to counteract the increase in temperature.
In summary, increasing the temperature from the equilibrium temperature will cause the reaction to shift in the direction that consumes heat, in this case, towards the products.