Openchemistry/Thermochemistry

Reaction Profiles
Exothermic

Endothermic

Products - Reactants

Enthalpy calculations
Working out the enthalpy of reaction

Rates of reaction
"More frequent effective collisions "

For a reaction to occur the particles need to collide with enough energy and the right orientation. If both of these conditions are meet then we have a successful  collision. The energy at the start of a reaction is to get over the activation energy.