It is clear how the total entropy of the universe increases in a spontaneous process through the mobility of particles during the interaction between the system and its surrounding. For instance, in an exothermic combustion reaction, a massive amount of entropic energy that is stored in a highly ordered structure is released to the surrounding when activated energy is provided to the system. It is to some extent counterintuitive to understand how an irreversible non-spontaneous process leads to an increase in the entropy of the universe as it seems some part of the transferred heat is being lost in the system and surrounding. Also, according to free energy formulas, a spontaneous process from the system's perspective may seem non-spontaneous from the surrounding's perspective. For instance, through a heat transfer from a hot surrounding to a cold system, the system's Gibbs free energy decreases, but it increases in the surrounding. Therefore, we should look at the total Gibbs free energy change or total entropy change of the universe to evaluate the spontaneity of a process.