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Energy Diagrams quiz #1

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  • Which topic is commonly used to explain activation energy and how chemical reactions happen?
    Energy diagrams are commonly used to explain activation energy and how chemical reactions occur by visually representing the energy changes during a reaction.
  • What does the energy hill represent on an energy diagram?
    The energy hill on an energy diagram represents the activation energy barrier that reactants must overcome to reach the transition state and form products.
  • What does the following energy diagram represent?
    An energy diagram represents the energy changes during a chemical reaction, showing the relative energies of reactants, products, and the transition state (activated complex).
  • Which part of the graph represents activation energy?
    The activation energy is represented by the vertical distance from the reactant energy level to the peak of the curve (the transition state) on the energy diagram.
  • In an energy-profile graph, the activated complex is represented at the:
    The activated complex (transition state) is represented at the highest point (peak) of the energy-profile graph.
  • Label the energy diagram (7 bins) and indicate which reaction corresponds to the energy diagram.
    Label the energy diagram as follows: (1) Reactants, (2) Activation energy (Ea), (3) Transition state (activated complex), (4) Reaction coordinate, (5) Products, (6) ΔE (overall energy change), (7) Exothermic or endothermic reaction. The reaction corresponds to either an exothermic process (products lower in energy than reactants) or endothermic (products higher in energy than reactants), depending on the diagram.
  • Label the energy diagram for a two-step reaction.
    For a two-step reaction, label: (1) Reactants, (2) First activation energy (Ea1), (3) First transition state, (4) Intermediate, (5) Second activation energy (Ea2), (6) Second transition state, (7) Products.
  • What does the x-axis represent in an energy diagram?
    The x-axis of an energy diagram represents the reaction coordinate, which tracks the progress of the reaction from reactants to products.
  • How does the height of the activation energy barrier affect the speed of a chemical reaction?
    A higher activation energy barrier results in a slower reaction because fewer molecules have enough energy to overcome it, while a lower barrier leads to a faster reaction.
  • What does a negative value for ΔE or ΔH indicate about the stability and energy of the products compared to the reactants?
    A negative ΔE or ΔH means the reaction is exothermic, with products lower in energy and more stable than the reactants.