rate of reaction

• How can rates of reactions be measured?

  By the amount of product used or the amount of product formed over time
• What is the formula for the rate of reaction based on the amount of reactant used?

  Rate of reaction = amount of reactant used / time
• What is the formula for the rate of reaction based on the amount of product formed?

  Rate of reaction = amount of product formed / time
• How can the quantity of reactant or product be measured?

  By mass in grams or by volume in cm³
• What are the units of rate of reaction?

  g/s or cm³/s
• How can the quantity of reactants be expressed in terms of moles?

  By using moles instead of mass or volume
• What are the units for the rate of reaction when using moles?

  mol/s
• How can the rate of reaction be determined graphically?

  By drawing tangents to curves and using the slope of the tangent
• What does the gradient of a tangent to the curve represent?

  It measures the rate of reaction at a specific time
• What are the factors that affect the rates of chemical reactions?

  • Concentration
  • Pressure
  • Surface area
  • Temperature
  • Catalysts
• What is collision theory?

  Chemical reactions can occur only when reacting particles collide with sufficient energy
• What is activation energy?

  The minimum amount of energy that particles must have to react
• How does increasing the concentration of reactants affect the rate of reaction?

  It increases the frequency of collisions and thus the rate of reaction
• How does increasing the temperature affect the rate of reaction?

  It increases the frequency of collisions and makes the collisions more energetic
• What are catalysts?


  Substances that speed up chemical reactions without being changed or used up
• What role do enzymes play in biological systems?

  Enzymes act as catalysts
• Are catalysts included in the equation for a reaction?

  No, catalysts are not included in the equation
• How do catalysts affect activation energy?

  Catalysts decrease the activation energy
• What do catalysts provide for a chemical reaction?

  A different pathway that has a lower activation energy