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

Quizplus · Accepted Answer

In order to calculate ΔH for the given reaction, we need to use the equation: ΔH = Σ nΔH(products) - Σ nΔH(reactants) where ΣnΔH is the sum of the enthalpies of formation of the products or reactants, multiplied by their stoichiometric coefficients. We can use the following values for the enthalpies of formation (in kJ/mol): CO₂(g) = -107.1 H₂O(l) = -285.8 C₂H₆(g) = 109.5 O₂(g) = 0 Using these values and the stoichiometric coefficients from the balanced equation, we can calculate: ΔH = (4 x -107.1 kJ/mol + 6 x -285.8 kJ/mol) - (2 x 109.5 kJ/mol + 7 x 0 kJ/mol) ΔH = -3120 kJ/mol Therefore, the answer is D, -3120 kJ.

At Constant Pressure,the Combustion of 15