Question

2 mol of Hg(g) is combusted in a fixed volume bomb calorimeter with excess of O₂ at 298 K and 1 atm into HgO(s). During the reaction, temperature increases from 298.0 K to 312.8 K. If heat capacity of the bomb calorimeter and enthalpy of formation of Hg(g) are 20.00 kJ K^-1 and 61.32 kJ mol^-1 at 298 K, respectively, the calculated standard molar enthalpy of formation of HgO(s) at 298 K is X kJ mol^-1. The value of |X| is ____.

[Given: Gas constant R = 8.3 J K^-1 mol^-1]

Answer 1

ΔT = 312.8 – 298 = 14.8

Molar heat capacity of calorimeter = 20 kJ K^-1

Heat released by combustion of 2 moles of Hg(g) 

= -20 x 14.8 

= -296 kJ

Comments

Excellent explanation