A one-step reaction has the following energy values along its reaction coordinate:…

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

A one-step reaction has the following energy values along its reaction coordinate: reactants at

40\,\text{kJ}

, transition state at

120\,\text{kJ}

, and products at

10\,\text{kJ}

. Which statement correctly describes the reaction’s overall energy change

\Delta E

and thermodynamic classification? (a)

\Delta E = +30\,\text{kJ}

; the reaction is endothermic (b)

\Delta E = -30\,\text{kJ}

; the reaction is exothermic (c)

\Delta E = -80\,\text{kJ}

; the reaction is exothermic (d)

\Delta E = -30\,\text{kJ}

; the reaction is endothermic