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

Question

Quizplus · Accepted Answer

First, we need to find the moles of propane:
n = m/M = 2.50 g / 44.1 g/mol = 0.0566 mol

Next, we use the given ΔH° to calculate the heat evolved:
ΔH = n × ΔH° = 0.0566 mol × (-2220 kJ/mol) = 125.7 kJ

Rounding to the nearest whole number, we get 126 kJ, which is answer choice 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