When is a reaction with a positive enthalpy spontaneous

Remember that, at equilibrium:. Using the appendix table of standard thermodynamic quantities, determine the temperature at which the following process is at equilibrium:. How does the value you calculated compare to the boiling point of chloroform given in the literature? The literature boiling point of chloroform is Privacy Policy. Skip to main content. Based on our data, we think this problem is relevant for Professor Smith's class at Tulsa Community College.

If you forgot your password, you can reset it. Join thousands of students and gain free access to 46 hours of Chemistry videos that follow the topics your textbook covers. Analytical Chemistry Video Lessons. Cell Biology Video Lessons. Genetics Video Lessons. Biochemistry Video Lessons. GOB Video Lessons. Microbiology Video Lessons. Calculus Video Lessons. Statistics Video Lessons. The change in Gibbs free energy is equal to the change in enthalpy minus the mathematical product of the change in entropy multiplied by the Kelvin temperature.

Keep in mind that the temperature in the Gibbs free energy equation is the Kelvin temperature, so it can only have a positive value. This corresponds to both driving forces being in favor of product formation. This corresponds to both driving forces working against product formation. It is the entropy term that favors the reaction. A common example of a process which falls into this category is the melting of ice see figure below. The freezing of water is an example of this type of process.

It is spontaneous only at a relatively low temperature. Allison Soult , Ph. Department of Chemistry, University of Kentucky. Learning Outcomes Describe the meaning of a spontaneous reaction in terms of enthalpy and entropy changes. Define free energy. Determine the spontaneity of a reaction based on the value of its change in free energy at high and low temperatures. Spontaneous Reactions A spontaneous reaction is a reaction that favors the formation of products at the conditions under which the reaction is occurring.

Once the reaction begins, it continues on its own until one of the reactants fuel or oxygen is gone. When the water is carbonated, only a small amount of carbonic acid is formed because the reaction is nonspontaneous. Public Domain; Baruchlanda.