A potential-energy profile lists the following bond-energy segments for the gas-phase reaction XY(g) + Z₂(g) → XZ(g) + YZ(g):
• Energy required to break the XY bond: 460 kJ mol⁻¹
• Energy required to break the Z–Z bond: 240 kJ mol⁻¹
• A dashed segment labeled “side process” shows 150 kJ mol⁻¹ (not part of the main reaction)
• Energy released when forming the X–Z bond: 350 kJ mol⁻¹
• Energy released when forming the Y–Z bond: 420 kJ mol⁻¹
Ignoring the side process, determine ΔH for the main reaction in kJ mol⁻¹.