Rate of forward reaction equals the rate of the reverse reaction
Concentrations are constant not equal
Collision Theory
A reaction is most likely to occur if reactant articles collide with proper energy and orientation
The Rate of a Chemical Reaction Depends on
- Temperature (increase temperature increases rate)
- Concentration (increase concentration increases rate)
- Surface Area ( increase surface area increases rate)
- Presence of Catalyst (increases rate)
Equilibrium systems will shift to relieve stress
- Temperature change: The addition of heat to an exothermic reaction will shift the equilibrium towards the reactants. The addition of heat to an endothermic reaction will shift the equilibrium towards the products
- Concentration change (gases and aqueous solutions only): Equilibrium will shift toward the side with lower concentration Ex. the addition of product or the removal of reactants will shift the equilibrium towards the reactants
- Pressure change (gases only): If pressure increases or volume decreases the equilibrium will shift toward the side with fewer moles of gas. If pressure decreases or volume increases the equilibrium will shift toward the side with greater moles of gas
- Effect of catalyst: lowers the activation energy but does not effect the equilibrium (provides an alternative reaction pathway)
Systems in nature tend to undergo changes toward lower energy and higher entropy
Table I - Heats of Reaction: Negative values are exothermic. Values are given for the number of moles (coefficients) shown in the equation.
Potential Energy Diagrams
Energy released or absorbed by a chemical reaction (heat of reaction) is equal to the difference between the potential energy of the products and the potential energy of the reactants
