9. rate equations

• What is the purpose of plotting graphs in rate equations?


  To monitor how quickly a reaction occurs
• How is the rate of reaction calculated from a graph?

  By finding the gradient of the graph
• What does the y-axis represent in the rate graph discussed?

  Volume of gas produced
• What does the x-axis represent in the rate graph discussed?

  Time
• What is the formula for calculating the gradient of a graph?

  Change in Y over change in X
• What is the recommended size for drawing a graph on graph paper?

  At least half the graph paper
• Why is it important to use a larger section of the graph for calculating gradients?

  It increases accuracy of results
• What is a tangent in the context of a curved graph?

  A line that meets a curve at a point
• How do you find the rate of reaction at a specific point on a curve?

  By drawing a tangent at that point
• What is the unit for the rate of reaction when measuring gas volume?

  Centimeters cubed per minute
• What does the rate equation link together?

  Rate with concentrations of substances
• What is the general form of a rate equation?

  Rate = K[A]^m[B]^n
• What does the order of a reaction indicate?

  How concentration affects the rate
• What is zero order in a reaction?

  No effect on rate from concentration change
• What happens to the rate in a first-order reaction when concentration doubles?

  The rate also doubles
• What is the effect of doubling concentration in a second-order reaction?

  The rate quadruples
• How are orders of reaction determined?

  By conducting experiments
• What is the rate constant denoted by in the rate equation?

  K
• What is the relationship between temperature and the rate constant K?

  K increases with temperature increase
• Why does increasing temperature increase the rate of reaction?

  Particles have more kinetic energy
• What must happen to the rate constant K to balance the rate equation when temperature increases?

  K must increase
• How can the rate of reaction be calculated?

  Using the rate equation
• How does increasing the temperature affect the rate of reaction?

  It increases the rate of reaction.
• What must increase to balance the rate equation when the rate increases?

  The rate constant K must increase.
• What remains constant regardless of temperature changes in a reaction?

  The concentrations of substances A and B.
• How can the rate of reaction be calculated?

  Using the rate equation.
• Given the concentrations of NO and O2, how do you calculate the rate of reaction?

  Substitute values into the rate equation.
• What is the rate constant K for the reaction?

  K = 700,000 moles$^{-2}$ dm$^{6}$s$^{-1}$.
• What is the calculated rate of reaction for the given concentrations?

  1. 3 x 10$^{-3}$ moles per dm$^{3}$ per second.
• Why do carbon monoxide and oxygen not appear in the rate expression?

  They are zero order with respect to the reaction.
• How do you calculate the rate constant K for a reaction?

  K = rate / concentration$^{2}$.
• What is the value of K calculated for the second reaction?

  K = 520 moles$^{-1}$ dm$^{3}$s$^{-1}$.
• What are the units for the rate of reaction?

  moles per dm$^{3}$ per second.
• How is the initial rate of reaction determined?

  Using the gradient of a tangent at time zero.
• What does the initial rate method help determine?

  The rate equation of a reaction.
• How do you find the order with respect to a reactant?

  By comparing experiments with varying concentrations.
• What is the rate equation for the reaction of nitrogen monoxide and chlorine?

  Rate = K [NO][Cl$_{2}$].
• What are the steps to determine the rate equation using initial rates method?

  1. Conduct experiments changing one reactant's concentration.
  2. Record initial rates for each experiment.
  3. Analyze data to find orders of reactants.
  4. Write the rate equation based on orders.
• What is the significance of the rate constant K in chemical reactions?

  • Indicates the speed of the reaction.
  • Depends on temperature and reaction conditions.
  • Used in rate equations to calculate reaction rates.
• What is the relationship between temperature, rate, and rate constant K?

  • Increasing temperature raises the rate.
  • Higher rate requires a higher K value.
  • K is temperature-dependent.