Delta G, also known as Gibbs free energy, is a thermodynamic quantity that measures the amount of energy available in a system to do useful work. It is important in scientific calculations because it helps determine whether a chemical reaction is spontaneous or non-spontaneous.
Delta G can be calculated using the equation ΔG = ΔH - TΔS, where ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy. In simpler terms, delta G is equal to the difference between the energy absorbed or released during a chemical reaction and the energy lost due to disorder in the system.
A positive value of delta G indicates that the reaction is non-spontaneous and requires energy to occur. A negative value of delta G indicates that the reaction is spontaneous and releases energy.
The value of delta G changes with temperature. As temperature increases, the value of delta G becomes less negative, eventually reaching a point where it becomes positive. This means that at higher temperatures, reactions that were previously spontaneous can become non-spontaneous.
The value of delta G is influenced by the enthalpy change, entropy change, and temperature of a system. Additionally, the concentration of reactants and products can also affect the value of delta G. Changes in pressure, pH, and catalysts can also impact the value of delta G.