Posted by Soojung on .
A 19th-century chemist, Marcellin Berthelot, suggested that all chemical processes that proceed spontaneously are exothermic.
True or False?
I thought it was true, but then in my chemistry textbook, I could not find this person's name. Can someone verify whether it is true or false?
Here is some information about Barthelot.
While it is true that MANY spontaneous reactions are exothermic, there are some endothermic reactions that are spontaneous. It is delta G (delta G = delta H -TtdeltaS) that must be negative to be spontaneous.
The statement is false, You got a perfect explanation from DrBob. Here is a less formal explanation based on the equation for deltaG:
Chemical and physical changes happen because of two universal trends:
A. A trend toward lower energy. This favors exothermic reactions as far as spontaneity goes.
B. A trend toward greater disorder (a rise in entropy). Greater disorder means formation of more particles, more mixing, and more particle motion. Increased temperature favors more disorder and spontaneity.
How the two trends work together, is described by the equation,