The complete combustion of propane, C₃H₈(g) , is represented by the equation: C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(l) ΔH° = -2220 kJ
How much heat is evolved in the complete combustion of 2.50 g C₃H₈(g) ?

Question

Quizplus · Accepted Answer

First, we need to calculate the number of moles of C₃H₈(g) present in 2.50 g of the substance. Molar mass of C₃H₈(g) = 44.1 g/mol Number of moles = Mass/Molar mass = 2.50 g/44.1 g/mol = 0.0566 mol Next, we use the balanced chemical equation and the given enthalpy change to calculate the heat evolved in the combustion of 0.0566 mol of C₃H₈(g). From the balanced equation, 1 mol of C₃H₈(g) produces 2220 kJ of heat. Therefore, 0.0566 mol of C₃H₈(g) will produce: Heat evolved = 0.0566 mol x 2220 kJ/mol = 125.5 kJ Rounding to the nearest whole number gives the answer of 126 kJ. Thus, the best choice is C.

The Complete Combustion of Propane, C3H8(g), Is Represented by the Equation

The Complete Combustion of Propane, C₃H₈(g), Is Represented by the Equation