Given: i C graphite + O 2 g → CO 2 g ; ΔrH Θ = x kJ mol - 1 ii C graphite + 1 2 O 2 g → CO g ; ΔrH Θ = y kJ mol - 1 iii CO g + 1 2 O 2 g → CO 2 g ; ΔrH Θ = z kJ mol - 1 Based on the above thermochemical equations, find out which one of the following algebraic relationships is correct?

Step-by-step solution

C + O 2 → CO 2 ,   ΔH = x We get the above equation by adding ( 2 ) and ( 3 ) C + 1 2 O 2 → CO                         ΔH = y CO + 1 2 O 2 → CO 2                                     ΔH = z C + O 2 → CO 2                         ΔH = x x = y