Calculate the standard molar heat of combustion of ethane. Given: Δ Hf o r m a t i o no of C2H6,CO2 and water (l) are, -21.1-94.1 and -68.3 kcal, respectively .

Question

Calculate the standard molar heat of combustion of ethane. Given: Δ Hf o r m a t i o no of C2H6,CO2 and water (l) are, -21.1-94.1 and -68.3 kcal, respectively . (A) -372 text Kcal (B) 162 textkcal (C) -240 textkcal (D) 183.5 textkcal

Tardigrade Admin · Accepted Answer

Given, 2C+3H2 arrow C2H6; Δ H=-21.1 C+O2 arrow CO2; Δ H=-94.1 H2+(1/2)O2 arrow H2O; Δ H=-68.3 Eqs .2(ii) + 3(iii) - (i) C2H6+(7/2)O2 arrow 2CO2+3H2O Δ x=2(- 94.1)+3(- 68.3)-(.-21.1.) =-372 kcal

Q. Calculate the standard molar heat of combustion of ethane.
Given: $Δ H_{_{f or ma t i o n}}^{o}$ of $C_{2} H_{6}, C O_{2}$ and water $(l)$ are, $- 21.1 - 94.1$ and $- 68.3$ kcal, respectively .

$- 372 Kcal$

$162 kcal$

$- 240$ $kcal$

$183.5 kcal$

Given, $2 C + 3 H_{2} \to C_{2} H_{6}; Δ H = - 21.1$
$C + O_{2} \to C O_{2}; Δ H = - 94.1$
$H_{2} + \frac{1}{2} O_{2} \to H_{2} O; Δ H = - 68.3$
Eqs .2(ii) + 3(iii) $-$ (i)
$C_{2} H_{6} + \frac{7}{2} O_{2} \to 2 C O_{2} + 3 H_{2} O$
$Δ x = 2 (- 94.1) + 3 (- 68.3) - (- 21.1)$
$= - 372 k c a l$

Q. Calculate the standard molar heat of combustion of ethane. Given: ΔHformation​o​ of C2​H6​,CO2​ and water (l) are, −21.1−94.1 and −68.3 kcal, respectively .

−372 Kcal

162kcal

−240 kcal

183.5kcal