A chemist is investigating the elementary gas-phase reaction
A(g) → B(g)
Standard enthalpy data obtained from calorimetric measurements indicate that the energy of the reactants can be taken as a reference point of 0 kJ mol⁻¹, the transition state lies at 120 kJ mol⁻¹, and the products lie at –40 kJ mol⁻¹ along the reaction coordinate.
Answer the following questions about this reaction energy profile.
(a) Sketch a fully-labeled reaction energy profile for the process, using the quantitative information above. Label the reactants (A), products (B), transition state, activation energy for the forward reaction, activation energy for the reverse reaction, and the overall energy change.
(b) Describe how the magnitude of the activation energy depicted in your sketch influences the observed reaction rate at constant temperature.
(c) Explain why the products are shown at a negative energy relative to the reactants and discuss what that implies about the thermodynamic favorability of the reaction.