Question

What is entropy and free energy?

Answer 1

Part 1: Entropy

1. Entropy of the system is a thermodynamic quantity that explains the disorder particles present in the system.
2. The SI unit of entropy is defined as Joules per Kelvin and is denoted by the letter “S”.
3. Entropy is also defined in terms of heat exchange and absolute temperature.
4. Entropy is the ratio of change in heat over absolute temperature where$∆\mathrm{S}={\left(\frac{∆\mathrm{Q}}{\mathrm{T}}\right)}_{\mathrm{rev}}$where, $∆\mathrm{S}$is the change in entropy, $∆\mathrm{Q}$ is the change in heat and T is the temperature.

Part 2: Free energy

1. Free energy or Gibbs free energy is defined as the difference between enthalpy with the product of temperature and entropy.
2. Gibbs free energy is denoted by the letter “G”
3. Gibbs free energy can be represented as follows:$∆\mathrm{G}=∆\mathrm{H}-\mathrm{T}∆\mathrm{S}$ where is $∆\mathrm{H}$ is the change in enthalpy, T is the temperature, and $∆\mathrm{S}$ is the change in entropy.
4. The negative value of Gibbs free energy denotes that process is spontaneous and the reaction will proceed in forward direction.
5. The positive value of Gibbs free energy denotes that the reaction proceeds in the backward direction.
6. If the value of Gibbs free energy is equal to 0 then reactions are in equilibrium.