At constant pressure,the combustion of 15.0 g of C₂H₆(g) releases 777 kJ of heat.What is ΔH for the reaction given below?
2 C₂H₆(g) + 7 O₂(g) → 4 CO₂(g) + 6 H₂O(l)

Question

At constant pressure,the combustion of 15.0 g of C₂H₆(g)releases 777 kJ of heat.What is ΔH for the reaction given below? 2 C₂H₆(g)+ 7 O₂(g)→ 4 CO₂(g)+ 6 H₂O(l)

Quizplus · Accepted Answer

The molar mass of C₂H₆ is 30.0 g/mol. Therefore, 15.0 g of C₂H₆ is 0.5 mol. Since 0.5 mol releases 777 kJ, 1 mol would release 1554 kJ. The reaction involves 2 mol of C₂H₆, so ΔH for the reaction is 2 * 1554 kJ = 3108 kJ, which is closest to option D (-3120 kJ).

At Constant Pressure,the Combustion of 15