For which of the following reactions, Δ H is equal to Δ U ?

Question

For which of the following reactions, Δ H is equal to Δ U ? (A) N2(g) + 3H2(g) -> 2NH3(g) (B) 2HI(g) -> H2(g) + I2(g) (C) 2NO2(g) -> N2O4(g) (D) 2SO2(g) + O2(g) -> 2SO3(g)

Tardigrade Admin · Accepted Answer

We know Δ H=Δ U+Δ ng R T where Δ n g = gaseous moles of products - gaseous moles of reactants For reaction 2 HI ( g ) arrow H 2( g )+ I 2( g ) ; Δ n g =2-2=0 Therefore, from Eq. (1), we get Δ H=Δ U

Q. For which of the following reactions, $Δ H$ is equal to $Δ U$ ?

$N_{2} (g) + 3 H 2 (g) - > 2 N H_{3} (g)$

$2 H I (g) - > H_{2} (g) + I_{2} (g)$

$2 N O_{2} (g) - > N_{2} O_{4} (g)$

$2 S O_{2} (g) + O_{2} (g) - > 2 S O_{3} (g)$

We know $Δ H = Δ U + Δ n_{g} RT$

where $Δ n_{g} =$ gaseous moles of products - gaseous moles of reactants

For reaction $2 H I (g) \to H_{2} (g) + I_{2} (g); Δ n_{g} = 2 - 2 = 0$

Therefore, from Eq. (1), we get

$Δ H = Δ U$

Q. For which of the following reactions, ΔH is equal to ΔU ?

N2​(g)+3H2(g)−>2NH3​(g)

2HI(g)−>H2​(g)+I2​(g)

2NO2​(g)−>N2​O4​(g)

2SO2​(g)+O2​(g)−>2SO3​(g)