The heat of combustion of C, S and CS2 are -393.3 kj, -293.7 kj and -1108.76 kj. What will be the heat of formation of CS2?

Question

The heat of combustion of C, S and CS2 are -393.3 kj, -293.7 kj and -1108.76 kj. What will be the heat of formation of CS2? (A) -128.02 kj (B) +970 kj (C) +1108.7 kj (D) +12 kj

Tardigrade Admin · Accepted Answer

C + 2S → CS2 Δ H = SigmaΔ HP - SigmaΔ HR = - 1108.76 - [-393.3+2 ×(-293.7)] = -1108.76 + 393.3 + 587.4 = -128.02 kj

Q. The heat of combustion of $C$ , $S$ and $C S_{2}$ are $- 393.3 kj$ , $- 293.7 kj$ and $- 1108.76 kj$ . What will be the heat of formation of $C S_{2}$ ?

$- 128.02 kj$

$+ 970 kj$

$+ 1108.7 kj$

$+ 12 kj$

$C + 2 S \to C S_{2}$
$Δ H = ΣΔ H_{P} - ΣΔ H_{R}$
$= - 1108.76 - [- 393.3 + 2 \times (- 293.7)]$
$= - 1108.76 + 393.3 + 587.4 = - 128.02 kj$

Q. The heat of combustion of C, S and CS2​ are −393.3kj, −293.7kj and −1108.76kj. What will be the heat of formation of CS2​?

−128.02kj

+970kj

+1108.7kj

+12kj