At constant temperature and pressure, if ΔH is positive and ΔS is negative, what

At constant temperature and pressure, if ΔH is positive and ΔS is negative, what is the sign of ΔG?

At constant temperature and pressure, if ΔH is positive and ΔS is negative, what is the sign of ΔG?

Step 1: Understand the symbols. ΔH represents the change in enthalpy (heat content), ΔS represents the change in entropy (disorder), and ΔG represents the change in Gibbs free energy.
Step 2: Identify the conditions given in the question. We have ΔH > 0 (positive) and ΔS < 0 (negative).
Step 3: Recall the formula for Gibbs free energy: ΔG = ΔH - TΔS, where T is the temperature in Kelvin.
Step 4: Since ΔH is positive, this means that the system is absorbing heat.
Step 5: Since ΔS is negative, this means that the disorder of the system is decreasing.
Step 6: When you multiply T (a positive value) by ΔS (which is negative), the result is negative. So, TΔS < 0.
Step 7: Now, substitute the values into the Gibbs free energy formula: ΔG = ΔH - TΔS. Since ΔH is positive and TΔS is negative, ΔG will be positive - positive minus a negative is positive.
Step 8: Therefore, if ΔH is positive and ΔS is negative, ΔG will always be positive.

Gibbs Free Energy – Gibbs Free Energy (ΔG) is a thermodynamic potential that measures the maximum reversible work obtainable from a thermodynamic system at constant temperature and pressure.
Enthalpy (ΔH) – Enthalpy (ΔH) is a measure of the total heat content of a system, and a positive ΔH indicates that the reaction is endothermic.
Entropy (ΔS) – Entropy (ΔS) is a measure of the disorder or randomness in a system, and a negative ΔS indicates a decrease in disorder.
Gibbs Free Energy Equation – The relationship between ΔG, ΔH, and ΔS is given by the equation ΔG = ΔH - TΔS, where T is the temperature in Kelvin.