A chemical reaction has a ΔH of –150 kJ mol⁻¹ and the activation energy for its reverse reaction is 350 kJ mol⁻¹ - VCE - SSCE Chemistry - Question 8 - 2007 - Paper 1

To find the activation energy of the forward reaction, we can use the relationship between the activation energies of the forward and reverse reactions:

$E_a^{forward} = E_a^{reverse} + ext{Δ}H$

Substituting the given values:

• Activation energy of the reverse reaction, $E_a^{reverse} = 350 ext{ kJ mol}^{-1}$
• Enthalpy change, $ΔH = -150 ext{ kJ mol}^{-1}$

Thus,

$E_a^{forward} = 350 ext{ kJ mol}^{-1} - 150 ext{ kJ mol}^{-1}$

Calculating this gives:

$E_a^{forward} = 350 - 150 = 200 ext{ kJ mol}^{-1}$

Therefore, the activation energy of the forward reaction is +200 kJ mol⁻¹.