Total Bond Energy Quick Check

When producing hydrogen iodide, the energy of the reactants is 581 kJ/mol, and the energy of the products is 590 kJ/mol. The equation is shown. H2 + I2 → 2HI What is the total energy of the reaction? Is this an endothermic or exothermic reaction?

-9 kJ/mol, exothermic

Hydrogen bromide breaks down into diatomic hydrogen and bromine in the reaction shown. 2HBr → H2 + Br2 The energy of the reactant is 732 kJ/mol, and the energy of the products is 630 kJ/mol. What is the total energy of the reaction? Is this reaction endothermic or exothermic?

102 kJ/mol, endothermic

Which result occurs during an exothermic reaction?

Light or heat are released into the environment.

Which event is an example of an endothermic reaction?

photosynthesis

How is total reaction energy calculated?

reactant bond energy - product bond energy