What is Delta S and Delta H?

In thermodynamics, ΔS and ΔH are symbols that represent changes in entropy and enthalpy, respectively:

ΔS (Delta S)
Entropy Change: Entropy (S) is a measure of the randomness or disorder of a system. ΔS represents the change in entropy during a process.
Units: Joules per Kelvin (J/K).
Positive ΔS: Indicates an increase in randomness or disorder.
Negative ΔS: Indicates a decrease in randomness or disorder.
ΔH (Delta H)
Enthalpy Change: Enthalpy (H) is the total heat content of a system at constant pressure. ΔH represents the change in enthalpy during a process.
Units: Joules (J) or kilojoules (kJ).
Positive ΔH: Indicates that the process is endothermic (absorbs heat from the surroundings).
Negative ΔH: Indicates that the process is exothermic (releases heat to the surroundings).
Relation to Spontaneity
The spontaneity of a process can be predicted using the Gibbs free energy change (ΔG), which combines both ΔH and ΔS:
Δ
𝐺
=
Δ
𝐻
−
𝑇
Δ
𝑆
ΔG=ΔH−TΔS

Where
𝑇
T is the temperature in Kelvin.
A negative ΔG indicates a spontaneous process, while a positive ΔG indicates a non-spontaneous process.