Chemistry - Thermochemistry Question with Solution | TestHub

C₆H₁₂ + 9O₂ ⎯→ 6CO₂ + 6H₂O; $\Delta H_1=-3920kJmo{l}^{-1}$ …(1)

(cyclohexane)

C₆H₁₀ + $\frac{17}{2}$O₂ ⎯→ 6CO₂ + 5H₂O; $\Delta H_2=-3800kJmo{l}^{-1}$ …(2)

H₂ + $\frac{1}{2}$O₂ ⎯→ H₂O; $\Delta H_3=-241kJmo{l}^{-1}$ …(3)

The required equation is:

C₆H₁₀ + H₂ ⎯→ C₆H₁₂; $\Delta H=?$ …(4)

Adding equation (2) and (3) and subtracting equation (1) from the sum, we get equation (4).

Therefore, $\Delta H=(\Delta H_2+\Delta H_3)-\Delta H_1$

$$=(-3800-241)-(-3920)kJ/mol$$

$$=-121kJmo{l}^{-1}$$