5.4 Potential Energy Profiles

Question 1

What does a potential energy profile show?

Answer 1

How the potential energy of the species involved in a chemical reaction changes during that reaction.

Question 2

What is important about the energy profile for an exothermic reaction?

Answer 2

The products have lower energy and are more stable than the reactants.

Question 3

What is important about the energy profile for an endothermic reaction?

Answer 3

The reactants have lower energy and are more stable than the products.

Question 4

How is the surface of the Earth protected from UV light?

Answer 4

By O2 and O3 in the atmosphere. Uv radiations absorbed by molecules of O2 and O3 as they undergo dissociation (O-O bond brown) O2 absorbs higher energy (higher/frequency/shorter wavelength) UV radiation than O3 - the bond between the O atoms in an O2 molecule is stronger (a double bond) than that in O3 (between a double bond and a single bond).