Kinetics AS

• What is the activation energy defined as?

  Minimum energy for collisions
• The Maxwell-Boltzmann distribution shows the spread of energies that molecules of a gas or liquid have at a particular temperature
• The Maxwell-Boltzmann distribution starts at the origin because no molecules have zero energy.
• The Maxwell-Boltzmann distribution meets the x-axis because there is a maximum energy for molecules.

  False
• What does the area under the Maxwell-Boltzmann curve represent?

  Total number of particles
• The Maxwell-Boltzmann distribution is not symmetrical, indicating that most molecules have energies between the two extremes
• What does Emp refer to in the Maxwell-Boltzmann distribution?

  Most probable energy
• Steps that occur as temperature increases in the Maxwell-Boltzmann distribution

  1️⃣ The distribution shifts towards higher energies

  2️⃣ The total area under the curve remains constant

  3️⃣ Both the Emp and mean energy increase
• What happens to the range of energies as temperature increases?

  The range becomes wider
• Activation energy is the minimum energy needed to break bonds in reactant molecules.
• The usual unit for reaction rate is mol dm-3s-1
• What is the initial rate of reaction?

  Rate at the start
• Higher concentrations lead to more frequent and effective collisions.
• What happens to the number of molecules with energy greater than EA when concentration increases?

  It increases
• In the reaction between sodium thiosulfate and hydrochloric acid, the cloudiness of the sulfur is used to measure the reaction time
• How does increasing surface area affect reaction rate?

  Increases successful collisions
• Catalysts increase reaction rates without being used up in the process.
• Catalysts provide an alternative reaction mechanism with a lower activation energy
• What happens to particle energy and collision frequency at higher temperatures?

  Both increase