3.5.1 Factors affecting rate

• The units of reaction rate are mol dm⁻³ s⁻¹
• How does increasing temperature affect reaction rate?

  Increases reaction rate
• Match the factor with its effect on reaction rate:

  Temperature ↔️ Increases kinetic energy

  Concentration ↔️ Increases collision frequency

  Catalyst ↔️ Provides lower activation energy

  Surface Area ↔️ Exposes more molecules to collisions
• Understanding reaction rates helps control chemical processes effectively.

  True
• What effect does higher concentration have on reaction rate?

  Increases reaction rate
• How does increased pressure affect the reaction rate of gas-phase reactions?

  Increases reaction rate
• Match the aspect of reaction rate with its description:

  Definition ↔️ Speed at which a chemical reaction occurs

  Measurement ↔️ Change in concentration per unit time

  Units ↔️ mol dm⁻³ s⁻¹ or M s⁻¹
• The reaction rate is measured as the change in concentration of reactants or products per unit time
• How does temperature affect reaction rate?

  Increases it
• Increased surface area of a solid reactant speeds up the reaction rate.


  True
• Higher concentration of reactants increases the frequency of effective collisions
• How does higher temperature affect the kinetic energy of reactant molecules?

  Increases it
• According to the Arrhenius equation, increasing temperature exponentially increases reaction rate.


  True
• What is the primary effect of a catalyst on reaction rate?

  Lowers activation energy
• Match the type of catalyst with its description:

  Homogeneous ↔️ Same phase as reactants

  Heterogeneous ↔️ Different phase from reactants
• Higher kinetic energy leads to more frequent and forceful collisions
• How does a catalyst affect the activation energy of a reaction?

  Lowers it
• Arrange the following steps in the effect of concentration on reaction rate according to Collision Theory.

  1️⃣ Higher concentration of molecules

  2️⃣ Increased frequency of effective collisions

  3️⃣ Faster reaction rate
• Effective collisions require molecules to overcome the activation energy
• Match the type of catalyst with its description:

  Homogeneous Catalyst ↔️ Exists in the same phase as reactants

  Heterogeneous Catalyst ↔️ Exists in a different phase from reactants
• What is the definition of reaction rate?

  Change in concentration per time
• Reaction rates help chemists understand and control chemical processes effectively.


  True
• Higher concentration increases the frequency of effective collisions
• How is reaction rate quantified?

  Change in concentration per time
• Arrange the factors affecting reaction rate in order of their increasing effect (assuming other factors remain constant):

  1️⃣ Concentration

  2️⃣ Temperature

  3️⃣ Catalyst

  4️⃣ Surface Area
• A lower concentration of reactants leads to a slower reaction rate.
• Higher pressure in gas-phase reactions increases the frequency of effective collisions.


  True
• What is the definition of reaction rate?

  Speed of chemical reaction
• Understanding reaction rates helps chemists predict outcomes of chemical processes.


  True
• Higher concentration of reactants increases the frequency of effective collisions
• What is the role of a catalyst in a reaction?

  Lowers activation energy
• Increasing pressure in gas-phase reactions increases reaction rate.


  True
• In heterogeneous reactions, increasing the surface area of the solid reactant enhances the frequency of effective collisions
• Homogeneous catalysts exist in the same phase as reactants.

  True
• What are the main factors affecting reaction rates?

  Temperature, concentration, surface area, catalyst
• Increased concentration of reactants increases the reaction rate.


  True
• A higher concentration of reactants means more molecules are available in the reaction mixture
• What effect does increased pressure have on the reaction rate of a gas-phase reaction?

  Increases it
• The Arrhenius equation describes the relationship between temperature and reaction rate.


  True
• What theory explains why catalysts increase reaction rates by providing alternative pathways?

  Collision Theory