Kinetics

• The energy required to start a reaction is called the activation energy.
• Activation energy is the minimum energy required to break bonds and start a reaction.
• Why do most collisions not lead to a reaction?

  Insufficient energy or wrong orientation
• The rate of reaction is defined as the change in concentration of a substance in a given time.
• As a reaction proceeds, the rate decreases due to the decreasing concentration of reactants.
• The rate at a particular time is equal to the gradient of the concentration-time graph.
• What happens to the reaction rate when the concentration of reactants increases?

  It increases
• Increasing the surface area of a solid increases the number of particles exposed, leading to more successful collisions.
• Increasing the temperature increases the reaction rate because more molecules have energy greater than the activation energy.
• How does a catalyst affect the activation energy of a reaction?

  It lowers the activation energy
• What is the advantage of using an initial rate method to monitor the rate of reaction?

  Monitors the reaction from the start
• To ensure accurate temperature measurements in kinetic experiments, it is recommended to measure both the initial and final temperatures.
• Sulfur dioxide produced in the reaction between sodium thiosulfate and hydrochloric acid is toxic.
• What is the purpose of a stop bath in kinetic experiments?

  Neutralizes acid and SO₂
• Arrange the key features of the Maxwell-Boltzmann distribution in a logical sequence:

  1️⃣ Area under the curve equals total molecules

  2️⃣ The shaded area is molecules with E > EA

  3️⃣ No molecules have zero energy

  4️⃣ Highest point is the most probable energy
• How does increasing temperature affect the peak of the Maxwell-Boltzmann distribution curve?

  Lower and moves to the right
• A small increase in temperature can cause a large increase in the number of molecules with energy greater than the activation energy.
• What is the effect of a catalyst on the activation energy of a reaction?

  Lowers the activation energy
• A catalyst changes the shape of the Maxwell-Boltzmann distribution curve.

  False
• Why does a small increase in temperature have a large effect on the initial rate of reaction?

  More molecules with E > EA