Rates of reaction

• Rate = change in concentration / time
• The rate is the slope of the tangent to the curve at any point.
• When the reactants are completely used up, the rate becomes zero.
• A straight line graph has a constant gradient, so it represents a constant rate.
• If the gradient increases or decreases with time, then the rate changes over time.
• Increase in temperature leads to an increase in rate due to increased kinetic energy of particles.
• Increasing temperature generally leads to an increase in rate due to increased kinetic energy of particles.
• Catalysts can be added to reactions to lower activation energies and increase rates without being consumed themselves.
• Concentration affects the rate of reaction as more collisions occur between molecules when they have higher concentrations.
• Catalysts do not affect the equilibrium position but can speed up reactions by providing alternative pathways.
• Decreasing surface area leads to a decrease in rate as there are fewer collisions between molecules.
• Catalysts lower activation energies by providing alternative pathways that have lower activation energies than the normal pathway.
• The concentration of reactants is directly proportional to the rate of reaction.
• Surface area is important because it provides more opportunities for collisions to take place.
• The effect of concentration on rate is explained by the collision theory, where increasing concentration increases the number of successful collisions per second.
• Reactions with high activation energies require large amounts of energy to overcome the barrier, making them slow at room temperature.
• Increasing temperature increases the kinetic energy of particles, leading to an increase in the number of successful collisions and therefore increasing the rate of reaction.