Question

Calculate the $△$H of the reaction

$H-\underset{\stackrel{|}{Cl}}{\stackrel{\underset{|}{H}}{C}}-Cl\left(g\right)⟶C\left(s\right)+2H\left(g\right)+2Cl\left(g\right)$

Bond energy for C-H bond & C-Cl bond are 415KJ and 326KJ respectively.

• A. -1482 kJ
• B. 1482 kJ
• C. 1483 kJ
• D. -1483 kJ

Answer 1

The correct option is B

1482 kJ

The enthalpy change can be given by:
$△$H = Sum of bond energies of reactants - sum of bond energies of products
$△$H = [2 × (C - H) + 2(C - Cl)] - 0
$△$H = 2 ×415 + 2 × 326

$△$H = 1482 KJ