What did the bartender say when oxygen hydrogen sulfur sodium and phosphorous walked into his bar? OH SNaP!

Potential Energy Diagrams

Types of Energy Kinetic  the energy of motion Potential  stored energy The total amount of energy in a system is conserved (no Energy lost) but it is converted (changed) into different forms

The energy of any object is the sum of its kinetic and potential energies At collision point, the energy in the system is 100% potential energy due to repulsion of valence electrons

Enthalpy ∆H Reactions give off heat energy ∆H = H products -H reactants H products > H reactants  endothermic (gets colder) H products < H reactants  exothermic (gets hotter)

PE diagram (exothermic) Insert from notes

Exothermic Examples – Burning – Heat packs

PE diagram (endothermic)

Endothermic Examples – Colp packs – Photosynthesis – Electrolysis of water

PE diagram (catalyst) +ve catalyzed reaction with have an increased reaction rate because the reactants can achieve a lower E A.

N2(g) + 2O2(g)  2NO 2(g) When ∆H = +10kcal and E A(f) = 65 kcal; include position of activated complex, a value for E A(f) and show the effect of a positive catalyst