2.4 g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atm pressure. The temperature of the calorimeter rises from 298 K to 300 K. The enthalpy change during the combustion of coal is - x kJ mol -1. The value of x is . (Nearest Integer) (Given: Heat capacity of bomb calorimeter 20.0 kJ K -1. Assume coal to be pure carbon)

Question

2.4 g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atm pressure. The temperature of the calorimeter rises from 298 K to 300 K. The enthalpy change during the combustion of coal is - x kJ mol -1. The value of x is . (Nearest Integer) (Given: Heat capacity of bomb calorimeter 20.0 kJ K -1. Assume coal to be pure carbon) (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

C ( s )+ O 2( g ) arrow CO 2( g ) ; Δ H =- x kJ / mole Q = C Δ T =20 kJ × 2 40 kJ heat is released for 2.4 g of C For 1 mole 'C': Q=(40/2.4) × 12 =(400/24) × 12=200 kJ / mole Q =Δ E =Δ H =200 kJ (∵ Δ n g =0) x =200

C(s)+O2​(g)→CO2​(g);ΔH=−xkJ/mole Q=CΔT=20kJ×2 40kJ heat is released for 2.4g of C For 1 mole 'C' : Q=2.440​×12 =24400​×12=200kJ/mole Q=ΔE=ΔH=200kJ(∵Δng​=0) x=200

$C (s) + O_{2} (g) \to C O_{2} (g); Δ H = - x k J / m o l e$
$Q = C Δ T = 20 k J \times 2$
$40 k J$ heat is released for $2.4 g$ of $C$
For $1$ mole ' $C$ ' :
$Q = \frac{40}{2.4} \times 12$
$= \frac{400}{24} \times 12 = 200 k J / m o l e$
$Q = Δ E = Δ H = 200 k J (∵ Δ n_{g} = 0)$
$x = 200$