Can an endothermic reaction be spontaneous?
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Can an endothermic reaction be spontaneous?
However, endothermic reactions do occur spontaneously, or naturally. There must be another driving force besides enthalpy change which helps promote spontaneous chemical reaction.
Can the same reaction be spontaneous and non-spontaneous?
The combination of energy decrease and entropy increase dictates that combustion reactions are spontaneous reactions. Fortunately, this reaction is nonspontaneous at normal temperatures and pressures. It is a highly endothermic reaction with a slightly positive entropy change (ΔS).
Can exothermic reactions be Nonspontaneous?
An exothermic reaction can be non-spontaneous when the temperature is high and entropy is negative, as shown in the ∆G = ∆H-T∆S equation.
Can an endothermic reaction or process be spontaneous if so give the conditions under which it would be spontaneous?
An endothermic reaction can only be spontaneous under standard conditions if the increase in molar entropy is sufficient to overcome the endothermicity. If Δ G is negative the reaction is spontaneous. Usually this equation is dominated by enthalpy changes but in rare cases entropy can determine spontaneity.
Are all endothermic reactions non-spontaneous?
Most endothermic reactions are non-spontaneous; without a steady supply of energy, the reactions typically come to a stop. An endothermic reaction can be spontaneous if entropy increases by more than the change in enthalpy.
When a reaction is non-spontaneous?
A nonspontaneous reaction is a reaction that does not favor the formation of products at the given set of conditions. In order for a reaction to be nonspontaneous, it must be endothermic, accompanied by a decrease in entropy, or both. Our atmosphere is composed primarily of a mixture of nitrogen and oxygen gases.
Is endothermic or exothermic spontaneous?
If a reaction is endothermic ( H positive) and the entropy change S is negative (less disorder), the free energy change is always positive and the reaction is never spontaneous….
| Enthalpy | Entropy | Free energy |
|---|---|---|
| exothermic, H < 0 | increased disorder, S > 0 | spontaneous, G < 0 |
What are non spontaneous reactions?
Non- Spontaneous reactions are those chemical reactions that require an energy input to proceed or that cannot take place without the influence of external factors. It requires energy input to proceed. Examples for non-spontaneous reactions are: Diffusion of gas from low pressure to a high pressure.
What is the difference between spontaneous and non spontaneous process?
Processes have a natural tendency to occur in one direction under a given set of conditions. A spontaneous process is one that occurs naturally under certain conditions. A nonspontaneous process, on the other hand, will not take place unless it is “driven” by the continual input of energy from an external source.
How can a non-spontaneous reaction be made spontaneous?
How can a non-spontaneous reaction be made spontaneous? This can be done by coupling with a spontaneous reaction with large –∆G. As a result, the overall ∆G for the coupled reaction will be negative. Above this temperature, ∆G will be negative and reaction becomes spontaneous.