In the reaction S+ (3/2)O2 → SO3 +2x : kJ and SO2+ (1/2)O2 → SO3+y kJ heat of formation of SO2 is

Question

In the reaction S+ (3/2)O2 → SO3 +2x : kJ and SO2+ (1/2)O2 → SO3+y kJ heat of formation of SO2 is (A) x + y (B) x - y (C) 2x + y (D) 2x - y

Tardigrade Admin · Accepted Answer

Key concept After applying Hess's law on the given reactions, we can get the value of heat of formation of

S O_{2}

. Hess's law states that the amount of heat evolved or absorbed in chemical change is same whether the process takes place in one step or multiple steps.

Given,

S + \frac{3}{2} O_{2} ⟶ S O_{3}, Δ H_{1} = - 2 \times k J

S O_{2} + \frac{1}{2} O_{2} \to S O_{3}, Δ H_{2} = - y X J

S + O_{2} \to S O_{2}, Δ H_{3} = - z X J

From Hess's law

Δ H_{3} + Δ H_{2} = Δ H_{1}

- z - y = - 2 x

\Rightarrow z = 2 x - y

Q. In the reaction
$S + \frac{3}{2} O_{2} \to S O_{3} + 2 x k J$ and $S O_{2} + \frac{1}{2} O_{2} \to S O_{3} + y k J$
heat of formation of $S O_{2}$ is

$x + y$

$x - y$

$2 x + y$

$2 x - y$

Q. In the reaction S+23​O2​→SO3​+2xkJ and SO2​+21​O2​→SO3​+ykJ heat of formation of SO2​ is

x+y

x−y

2x+y

2x−y

Q. In the reaction
$S + \frac{3}{2} O_{2} \to S O_{3} + 2 x k J$ and $S O_{2} + \frac{1}{2} O_{2} \to S O_{3} + y k J$
heat of formation of $S O_{2}$ is

$x + y$

$x - y$

$2 x + y$

$2 x - y$