For a certain reaction, the enthalpy change is -148.5 kJ, the entropy change is 256 J/K, and the free energy change is -250.1 kJ. At what temperature is the reaction occurring, in C?
Choose one answer. a. 85
b. 102
c. 124
d. 158
e. 210
delta G = delta H -T*delta S.
You have all of the numbers. Just plug them in and solve for T. Remember to convert T(in Kelvin) to C since the answer is to be in C.
To determine the temperature at which the reaction is occurring, we need to use the equation:
ΔG = ΔH - TΔS
where ΔG is the free energy change, ΔH is the enthalpy change, ΔS is the entropy change, and T is the temperature in Kelvin.
We can rearrange the equation to solve for T:
T = (ΔH - ΔG) / ΔS
Let's substitute the given values:
T = (-148.5 kJ - (-250.1 kJ)) / (256 J/K)
First, we need to convert all the units to the same form.
-148.5 kJ = -148.5 x 10^3 J (since 1 kJ = 1000 J)
-250.1 kJ = -250.1 x 10^3 J
256 J/K remains unchanged
Now let's substitute the values:
T = (-148.5 x 10^3 J - (-250.1 x 10^3 J)) / (256 J/K)
T = (101.6 x 10^3 J) / (256 J/K)
Now we can cancel out the unit of Joules (J) and simplify the expression:
T = 101.6 x 10^3 / 256 K
T = 397.5 K
To convert from Kelvin (K) to Celsius (C), we subtract 273.15 from the temperature:
T = 397.5 K - 273.15
T ≈ 124.4 C
So the temperature at which the reaction is occurring is approximately 124.4 degrees Celsius.
Therefore, the correct answer is c. 124.