Sulphur (2.56 g ) is burned in a constant volume calorimeter with excess O 2( g ). The temperature increases from 21.25° to 26.72° C. The bomb has a heat capacity of 923 JK -1. Calorimeter contains 815 g of water. Thus, change in internal energy per mole of SO 2 formed for the reaction is S 8( s )+8 O 2( g ) longrightarrow 8 SO 2( g ) (specific heat of water is 4.184 JK -1 g -1 ).

Question

Sulphur (2.56 g ) is burned in a constant volume calorimeter with excess O 2( g ). The temperature increases from 21.25° to 26.72° C. The bomb has a heat capacity of 923 JK -1. Calorimeter contains 815 g of water. Thus, change in internal energy per mole of SO 2 formed for the reaction is S 8( s )+8 O 2( g ) longrightarrow 8 SO 2( g ) (specific heat of water is 4.184 JK -1 g -1 ). (A) - 296.27 kj (B) + 296.27 kj (C) - 2370.13 kj (D) + 2370.13 kj

Tardigrade Admin · Accepted Answer

Moles of S8=(2.56/256)=0.01 Moles of SO 2 formed =0.08 Rise in temperature =(273+26.72) K -(273+21.25) K =5.47 K Total change in internal energy (as system is at constant volume) =-(923 JK -1 × 5.47 K +815 g × 4.184 JK -1 g -1 × 5.47 K ) =-23701.29 J =-23.70129 kJ Thus, change in internal energy per mole of SO 2 formed =-(23.7012 g/0.08)=-296.3 kJ mol -1