7.1.4 Interpreting Rate Graphs

• What is the relationship between volume and time shown in the graph?

  Volume increases over time
• In the graph "Concentration vs time", which variable is independent?

  Time is the independent variable
• What do different shapes of rate graphs indicate?

  • Linear shape: constant rate of reaction
  • Exponential shape: increasing rate of reaction
  • Sigmoidal shape: gradual increase, then plateau
• What does analyzing the shape of a rate graph provide clues about?

  Reaction kinetics
• How does the rate of reaction change during a chemical reaction?

  It decreases as reactants are used up
• What do these graphs show regarding reactant concentration [X]?

  They show changes over time or with concentration.
• Where does the independent variable go on a graph?

  On the x-axis
• If the reaction is "Reaction slower", what would the curve look like compared to the "Reaction faster" curve?

  The curve would be less steep
• What does the rate of reaction refer to?

  Speed at which reactants turn into products
• What does the arrow labeled $AC_1$ represent in the image?


  Activation complex 1
• What is activation energy?

  Minimum energy for a reaction
• What happens to the slope of the graph as the reaction proceeds?

  The slope becomes less steep over time
• In the image, how does activation energy 1 ($E_{a1}$) compare to activation energy 2 ($E_{a2}$)?


  $E_{a1}$ is greater than $E_{a2}$
• What does the arrow labeled $AC_2$ represent in the image?


  Activation complex 2
• When is the rate of reaction fastest according to the graph?

  Initially, at the steepest slope
• What does the slope become when the reaction is complete?

  Zero
• What does a higher activation energy (Ea) imply about a reaction step?

  It requires more energy to proceed
• What is another factor that affects the reaction rate?

  Concentration
• What are the two main types of rate graphs?

  Concentration vs Time and Rate vs Concentration
• What is Ea2 in the context of the graph?

  Energy to reach the second transition state
• What does the arrow labeled $E_{a2}$ represent in the image?


  Activation energy 2
• What are the key differences between the "Reaction faster" and "Reaction slower" curves?

  • "Reaction faster" curve is steeper, indicating a higher reaction rate
  • "Reaction slower" curve is less steep, indicating a lower reaction rate
  • The two curves reach the same final volume, but at different rates over time
• What can be inferred about the reaction rate of the two reactions depicted in the image, based on their activation energies?

  • Reaction 2 will proceed faster than reaction 1
  • Lower activation energy in reaction 2
  • Higher activation energy in reaction 1
• What do linear, exponential, and sigmoidal shapes of rate graphs suggest?

  They suggest different reaction progressions
• What does each peak on the energy profile indicate?

  The activation energy (Ea) for steps
• Why does a higher concentration lead to a higher reaction rate?

  More reactant molecules mean more successful reactions
• What are the three types of reaction orders shown in the image?

  Zero order, first order, and second order
• What does the arrow labeled $E_{a1}$ represent in the image?


  Activation energy 1
• How does the rate vs concentration graph appear for second order reactions?

  It appears as a curved line.
• If a reaction is zero order, what does that mean about the rate of the reaction?

  The rate of the reaction is constant over time
• What is the role of a catalyst in a chemical reaction?

  It speeds up the reaction mechanism
• What is the dependent variable in rate graphs?

  What you measure, like concentration
• What is the independent variable in rate graphs?

  What you change, usually time
• What does reaction kinetics describe?

  How fast a reaction happens
• What does the overall energy change (ΔG) indicate about a reaction?

  It indicates the spontaneity of the reaction
• Why does an increase in temperature lead to a higher reaction rate?

  More molecules have energy to overcome activation energy
• In the graph "Concentration vs time", which variable is dependent?

  Concentration is the dependent variable
• How does concentration affect the reaction rate?

  It increases the rate by increasing collisions
• Where does the dependent variable go on a graph?

  On the y-axis
• What do energy barriers in a reaction mechanism represent?

  The activation energy needed for steps