Which of the following statements concerning potential energy diagrams is true?
a) The activation energy of a reaction is proportional to its enthalpy change
b) The peak on this diagram represent an ineffective collision
c) The activation energy is measured from the origin to the top of the peak
d) The activation energy of the reverse reaction may be calculated from the diagram
e) The units of the diagram are joules and number of molecules
c) The activation energy is measured from the origin to the top of the peak
I thought it was d) ?
Apologies for the confusion. You are correct. The correct statement is d) The activation energy of the reverse reaction may be calculated from the diagram.
To determine which of the statements about potential energy diagrams is true, let's analyze each option:
a) The activation energy of a reaction is proportional to its enthalpy change:
This statement is not true. The activation energy and enthalpy change are different concepts and are not directly proportional to each other.
b) The peak on this diagram represents an ineffective collision:
This statement is not true. The peak on a potential energy diagram represents the transition state, where reactants are forming products. It does not necessarily imply an ineffective collision.
c) The activation energy is measured from the origin to the top of the peak:
This statement is true. Activation energy refers to the minimum amount of energy required for a reaction to occur. It is measured from the lowest energy point of the reactants to the highest energy point on the potential energy diagram, which corresponds to the top of the peak.
d) The activation energy of the reverse reaction may be calculated from the diagram:
This statement is not true. The activation energy of the reverse reaction cannot be directly calculated from the potential energy diagram. The diagram provides information about the energy changes during the forward reaction, but not the reverse reaction.
e) The units of the diagram are joules and the number of molecules:
This statement is not true. The units of a potential energy diagram are typically in joules for the energy axis, representing the potential energy of the system. The x-axis represents the reaction progress or reaction coordinate, not the number of molecules.
Therefore, the correct statement among the given options is c) The activation energy is measured from the origin to the top of the peak.