Here we're going to see that the Gibbs free energy formula allows us to calculate the value of delta G typically in units of kilojoules by using the change in the standard enthalpy, change in our standard entropy and temperature in Kelvin values.

Now here we need to note that the change in the standard Gibbs free energy change is under standard conditions, while delta G without the little not sign is under non standard conditions. Here when we're talking about standard conditions, we're going to say that

ΔG ° = ΔH ° - T ΔS °

And here we're going to say that under standard conditions we're talking about a pressure of one atmosphere, a temperature of 25°C.