Can spontaneous processes be endothermic?

For endothermic reactions, enthalpy usually goes up. However, a spontaneous endothermic reaction can occur when the changes in enthalpy and entropy yield a negative Gibbs free energy. An endothermic reaction can be spontaneous if entropy increases by more than the change in enthalpy.

Does exothermic mean spontaneous?

An exothermic reaction is when a reaction has a net release of heat, system loses heat (ΔH is negative). Spontaneous means that the reaction happens without any added help (ie. any extra energy).

Do all spontaneous processes release heat?

A spontaneous reaction always releases heat. The entropy of a system and its surroundings always increases for a spontaneous change.

Are all non spontaneous processes endothermic?

Therefore, spontaneity does not dictate whether a reaction is endothermic or exothermic. A spontaneous reaction is more likely to be exothermic but can be endothermic. Non-spontaneous reactions are more likely to be endothermic but can be exothermic.

Are all reactions spontaneous?

In this case, a spontaneous reaction is dependent upon the TΔS term being small relative to the ΔH term, so that ΔG is negative. The freezing of water is an example of this type of process. It is spontaneous only at a relatively low temperature. Above 273….Gibbs Free Energy.

ΔH	ΔS	ΔG
positive	negative	always positive

Are all combustion reactions spontaneous?

The products of a fire are composed partly of gases such as carbon dioxide and water vapor. The entropy of the system increases during a combustion reaction. The combination of energy decrease and entropy increase dictates that combustion reactions are spontaneous reactions.

Do spontaneous reactions always release energy?

Spontaneous reactions release free energy as they proceed. Recall that the determining factors for spontaneity of a reaction are the enthalpy and entropy changes that occur for the system. The free energy change of a reaction is a mathematical combination of the enthalpy change and the entropy change.

What makes an endothermic reaction spontaneous?

A spontaneous endothermic reaction can occur when the changes in enthalpy and entropy yield a negative Gibbs free energy. An endothermic reaction can be spontaneous if entropy increases by more than the change in enthalpy.

Why are all spontaneous processes not exothermic?

All spontaneous processes are not exothermic, because it is the Gibbs Free energy that determines spontaneity, not the enthalpy. A process is spontaneous if the Gibbs free energy is negative. An important expression for the Gibbs free energy is given by.

What is an exothermic reaction?

An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction. An exothermic reaction is a chemical or physical reaction that releases heat. It gives net energy to its surroundings. That is, the energy needed to initiate the reaction is less than the energy released.

How do you know if a process is spontaneous?

A process is spontaneous if the Gibbs free energy is negative. An important expression for the Gibbs free energy is given by You will notice that this expression may be positive even with a negative enthalpy change (exothermic process) if the entropy change is negative and the temperature is high enough.

What are the conditions under which a chemical reaction is spontaneous?

All the reactants are mono-atomic gases, and the product is a solid. This is a strong indication that the entropy of the system decreases. The reaction is spontaneous That statement from the text of the question means that the Gibbs energy of reaction is negative. It is not clear if this refers to standard conditions, or to the current conditions.