Spontaneous vs. nonspontaneous

[Esmeralda Polanco]

How can we differentiate between spontaneous and nonspontaneous?

[mact14a 1D]

Hi! from my understanding a spontaneous process would not input from the surroundings into the system or extra energy to proceed whilst a non spontaneous reaction would require energy from the surroundings, so to understand if something is spontaneous or not it would be helpful to examine the flow of energy and see if energy is going into or out of the system.

[sadie_remillard_1A]

Hi Esmeralda,
Spontaneous reactions happen by themselves without any extra heat or energy needed for them to occur and thus will be exothermic (negative enthalpy). A non-spontaneous reaction is when the reaction will not occur unless extra heat or energy is applied and thus will be endothermic (positive enthalpy).

[Sophia Lim 2A]

In thermodynamics, the terms "spontaneous" and "nonspontaneous" refer to the direction in which a process occurs. These terms are associated with changes in thermodynamic properties, especially the Gibbs free energy (ΔG). A process is considered spontaneous if it can occur on its own without any external influence. A process is considered nonspontaneous if it does not occur on its own and requires an external influence to proceed.

[Destiny Caldwell 3J]

Spontaneous processes: Often involve an increase in entropy and/or a decrease in enthalpy. Non-spontaneous processes: Often involve a decrease in entropy and/or an increase in enthalpy ().