Given R = 8.314 JK-1 mol-1 , the work done during combustion of 0.090 kg of ethane (molar mass = 30) at 300 K is

Question

Given R = 8.314 JK-1 mol-1 , the work done during combustion of 0.090 kg of ethane (molar mass = 30) at 300 K is (A) -18.7 kJ (B) 18.7 kJ (C) 6.234 kJ (D) - 6.234 kJ

Tardigrade Admin · Accepted Answer

Since, combustion takes place at constant pressure, hence Δ H=3 W Δ H =n Cp d T ⇒ 3 W =(0.090/30) × (5/2) × 8.314 × 300 =18.7 kJ

Q. Given $R = 8.314 J K^{- 1} m o l^{- 1}$ , the work done during combustion of $0.090 k g$ of ethane (molar mass = $30$ ) at $300 K$ is

$- 18.7 k J$

$18.7 k J$

$6.234 k J$

$- 6.234 k J$

Since, combustion takes place at constant pressure, hence

$Δ H = 3 W$

$Δ H = n C_{p} d T$

$\Rightarrow 3 W = \frac{0.090}{30} \times \frac{5}{2} \times 8.314 \times 300$

$= 18.7 k J$

Q. Given R=8.314JK−1mol−1 , the work done during combustion of 0.090kg of ethane (molar mass =30) at 300K is

−18.7kJ

18.7kJ

6.234kJ

−6.234kJ