Question

What does ∆G equal in nonstandard conditions?

a) ∆G = ∆H - T∆S
b) ∆G = ∆H + T∆S
c) ∆G = ∆H/T
d) ∆G = ∆H - T/∆S

Answer 1

The correct formula for ΔG under nonstandard conditions is ΔG = ΔH - TΔS, which corresponds to choice (a). This equation helps determine the spontaneity of a reaction under varying conditions.

Step-by-step explanation:

The correct formula for calculating the change in free energy (ΔG) under nonstandard conditions is ΔG = ΔH - TΔS, where ΔH stands for the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy. The most accurate answer to your question is ΔG = ΔH - TΔS, making choice (a) the correct option. It is essential to note that this equation applies to both standard and nonstandard conditions, as ΔG can vary when the conditions deviate from the standard state parameters (1 bar for pressure and 1 M for concentrations).

When calculating the standard free energy change for a reaction occurring at room temperature (ΔG°), we use standard enthalpies (ΔH°) and standard entropies (ΔS°) of reaction or formation. This allows us to predict whether a reaction is spontaneous or nonspontaneous. A negative ΔG indicates spontaneity, whereas a positive ΔG suggests nonspontaneity under the given conditions.