Topic 6 - Chemical Kinematics

• Rate of Reaction

  The change in concentration of reactants or products per unit time. It can be expressed as the decrease in concentration of reactants or the increase in concentration of products over time.

  Equation: $\text{Rate of Reaction} =$$\frac{\Delta [\text{Product}]}{\Delta t} \text{ or } \frac{-\Delta [\text{Reactant}]}{\Delta t}$
• Activation Energy ($E_a$​)


  The minimum amount of energy required for reactants to transform into products in a chemical reaction. It's the energy barrier that must be overcome for a reaction to proceed.
• Catalyst

  A substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself. Catalysts work by providing an alternative reaction pathway with a lower activation energy.
• Initial Rate of Reaction

  The rate at which reactants are converted into products at the beginning of the reaction, typically measured immediately after the reactants are mixed and the reaction begin
• Collision Theory


  Collision Theory states that chemical reactions can only occur when reacting particles collide with sufficient energy and the correct orientation. The energy must be greater than or equal to the activation energy of the reaction.
• Orientation Factor

  The orientation factor (or steric factor) refers to the requirement that reacting particles must be oriented in a certain way during a collision for a reaction to occur. Not all collisions, even those with sufficient energy, lead to a reaction due to incorrect orientation.
• Energy of Collision Factor

  Energy of collision refers to the kinetic energy particles have when they collide. For a reaction to occur, this energy must meet or exceed the activation energy, the minimum energy barrier for a reaction.
• Surface Area's Effect on Reaction Rate

  Increasing the surface area of a solid reactant exposes more particles to collisions, enhancing the reaction rate, particularly in reactions involving solids and gases or liquids.
• Concentration's Effect on Reaction Rate

  Increasing the concentration of reactants increases the number of particles in a given volume, leading to more frequent collisions and a higher rate of reaction.
• Catalyst's Effect in Reaction Rate

  Catalysts increase the rate of reaction by providing an alternative pathway with a lower activation energy, leading to more effective collisions without being consumed in the process.
• Temperature's Effect on Reaction Rate

  Increasing the temperature increases the kinetic energy of the particles, leading to more collisions and a higher probability of effective collisions, thus increasing the reaction rate.
• Effect of Pressure on Rate of Reaction

  In gas-phase reactions, increasing pressure boosts the reaction rate by raising reactant concentration, leading to more frequent effective collisions.