The polymerization of propene to linear polypropene is represented by the reaction Where n has large integral value, the average enthalpies of bond dissociation for (C=C) and (C-C) at 298 K are +590 and +331 kJ mol -1, respectively. The enthalpy of polymerization is -360 kJ -1. Find the value of n

Question

The polymerization of propene to linear polypropene is represented by the reaction <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/024ce993cc1e97189001f4836eb6622c-.png" /> Where n has large integral value, the average enthalpies of bond dissociation for (C=C) and (C-C) at 298 K are +590 and +331 kJ mol -1, respectively. The enthalpy of polymerization is -360 kJ -1. Find the value of n (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Energy released = Energy due to formation of two single bonds =2 × 331=662 kJ mol -1 of propene Δ H polymerization / mol =590-662= -72 kJ mol -1 Δ H polymerisation =-72 × n=-360 n=5

Energy released = Energy due to formation of two single bonds =2×331=662kJmol−1 of propene ΔH polymerization /mol=590−662= −72kJmol−1 ΔH polymerisation =−72×n=−360 n=5

Energy released $=$ Energy due to formation of two single bonds
$= 2 \times 331 = 662 k J m o l^{- 1}$ of propene
$Δ H$ polymerization $/ m o l = 590 - 662 =$
$- 72 k J m o l^{- 1}$
$Δ H$ polymerisation $= - 72 \times n = - 360$
$n = 5$