J.R. S. answered • 09/12/20
Ph.D. University Professor with 10+ years Tutoring Experience
Exothermic - heat is released from the system to the surroundings
...example would be combustion
Endothermic - heat is absorbed by the system from the surroundings
... example would be photosynthesis
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In an endothermic reaction, you might expect the test tube or beaker to get colder as heat is absorbed by the system (reaction). In an exothermic reaction, the opposite would be expected (test tube or beaker would get warmer) as heat is released by the system (reaction).
In an endothermic reaction, the energy of the products is greater than that of the reactants (∆H is positive). In an exothermic reaction, the energy of the products is less than that of the reactants (∆H is negative).
