rates of reaction

• What is the rate of a reaction?

  How quickly reactants are used or products produced
• What is the equation for calculating the mean rate of reaction?

  Mean rate = change in quantity / time taken
• What is the unit for rate of reaction in a reaction involving a change in mass?

  g/s
• What is the unit for rate of reaction in a reaction involving a change in volume?

  cm³/s
• What is the activation energy?

  The minimum energy needed for a reaction
• What effect does increasing concentration have on the rate of reaction?

  It increases the rate of reaction
• Why does increasing concentration have this effect?

  More particles lead to more frequent collisions
• What effect does increasing pressure have on the rate of reaction?

  It increases the rate of reaction
• Why does increasing pressure have this effect?

  Less space means more frequent collisions
• What effect does increasing surface area have on the rate of reaction?

  It increases the rate of reaction
• Why does increasing surface area have this effect?

  More particles are exposed for collisions
• What effect does increasing temperature have on the rate of reaction?

  It increases the rate of reaction
• Why does increasing temperature have this effect?

  Particles move faster, leading to more collisions
• What is a catalyst?

  A substance that increases reaction rate
• How do catalysts increase the rate of a reaction?

  They lower the activation energy needed
• What is the rate of a reaction?

  How quickly reactants turn into products
• How can you calculate the mean rate of reaction?

  Quantity of reactant used divided by time taken
• What is another way to calculate the mean rate of reaction?

  Quantity of product formed divided by time taken
• How can you measure the rate of a reaction involving a gas?

  By measuring mass change or gas volume
• What is the formula for the rate of reaction involving gas?

  Rate = volume of gas produced divided by time taken
• What are the units for measuring the rate of reaction involving gas?

  cm³/s
• How can you determine the mean rate of reaction between two points in time?

  By measuring change in mass over time
• What is the formula for the rate of reaction based on mass change?

  Rate = change in mass divided by time taken
• What are the units for measuring the rate of reaction based on mass change?

  g/s
• What does a steep gradient on a reaction graph indicate?

  A high rate of reaction
• What does a shallow gradient on a reaction graph indicate?

  A low rate of reaction
• How do you find the rate at a specific time from a graph?

  Draw a tangent and calculate its gradient
• How is the gradient of a tangent calculated?

  Change in y divided by change in x
• What is activation energy?

  The energy needed for particles to react
• What is required for a reaction to occur according to collision theory?

  Reactant particles must collide with enough energy
• How can the rate of a reaction be increased?

  By increasing collision frequency and energy
• What conditions increase the rate of reaction?

  • Increasing temperature: particles move faster
  • Increasing concentration: more reactant particles
  • Increasing pressure: less space between gas particles
  • Increasing surface area: more exposed reactant particles
• What is a catalyst?

  A substance that increases reaction rate
• How does a catalyst affect activation energy?

  It provides a pathway with lower activation energy
• What are the key terms related to rate of reaction?

  • Activation energy
  • Catalyst
  • Collision
  • Collision theory
  • Frequency of collision