What is the difference between a spontaneous and a non spontaneous reaction?

from my previous knowledge i remember that non spontaneous reactions does not react under normal conditions, it need different variables to cause a reaction to occur such as temperature (i.e heating)

If a reaction is spontaneous that means the reaction will go as written. It doesn't say anything how fast it will go or how long it will take but the reaction will produce more products and the reactants will be used. Non-spontaneous means that the reaction, as written, will not go but it will go in the reverse direction.

The difference between a spontaneous and a non-spontaneous reaction lies in the direction in which the reaction proceeds.

A spontaneous reaction is a reaction that occurs naturally and proceeds without any external influence. It is characterized by a decrease in the overall free energy of the system. In other words, during a spontaneous reaction, the reactants have a higher free energy than the products, and the reaction tends to move in the direction that decreases the free energy. Spontaneous reactions are generally exothermic (release heat) and can occur on their own without any additional energy input.

On the other hand, a non-spontaneous reaction is a reaction that does not occur naturally and does not proceed without external influence. It is characterized by an increase in the overall free energy of the system. In non-spontaneous reactions, the reactants have a lower free energy than the products, and the reaction tends to move in the direction that increases the free energy. Non-spontaneous reactions are generally endothermic (require heat input) and do not occur on their own.

To determine whether a reaction is spontaneous or non-spontaneous, you can use the concept of Gibbs free energy (ΔG). ΔG is a measure of the energy available to do work in a system. If ΔG is negative, the reaction is spontaneous and can occur without additional energy input. If ΔG is positive, the reaction is non-spontaneous and requires external energy input to proceed. Additionally, if ΔG is zero, the reaction is at equilibrium - meaning that the forward and reverse reactions occur at equal rates, and there is no net change in the system.

The calculation for Gibbs free energy takes into account the enthalpy (ΔH) and entropy (ΔS) changes of the reaction using the equation: ΔG = ΔH - TΔS, where T is the temperature in Kelvin.

So, in summary, the main difference between a spontaneous and a non-spontaneous reaction lies in the direction of the reaction and the overall change in free energy. Spontaneous reactions occur naturally, move towards lower free energy, and do not require additional energy input, while non-spontaneous reactions do not occur naturally, move towards higher free energy, and require external energy input to proceed.