Rate + extent of chemical change

• Increasing concentration of reactions, pressure of reacting gases, and surface area of solid reactions increase frequency of collision, which increases rate of reaction.

  Increasing the temperature increases frequency of collisions and make collisions more energetic which increases rate of reactions.
• According to the collision theory, chemical reactions can only occur when the reactants collide with each other and with sufficient energy.

  the minimum amount of energy that particles must have to react is called the activation energy