Molecules and have potential-energy minima given below

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

Problem

Molecules

C_{2}

and

D_{2}

have potential-energy minima given below. •

C_{2}

: minimum potential energy =

-4.0\,\text{eV}

per bond at

105\,\text{pm}

•

D_{2}

: minimum potential energy =

-350\,\text{kJ mol}^{-1}

115\,\text{pm}

(1\,\text{eV} \approx 96.5\,\text{kJ mol}^{-1})

Which molecule has the greater bond energy, and by approximately how much? (a)

\mathrm{D_{2}},\,\text{by about }40\,\text{kJ mol}^{-1}

(b)

\mathrm{C_{2}},\,\text{by about }40\,\text{kJ mol}^{-1}

(c)

\mathrm{C_{2}},\,\text{by about }140\,\text{kJ mol}^{-1}

(d)

\mathrm{D_{2}},\,\text{by about }350\,\text{kJ mol}^{-1}