Question

For this reaction, C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O, the ∆H is –2200 kJ. If two moles of C3H8(g) reacted with excess oxygen, what would be true?
A) 4400 kj of heat released into surroundings
B) 4400 kj of heat absorbed by system
C) 1100 kJ heat released into surroundings
D) 1100 kJ heat absorbed by system

Answer 1

A) 4400 kj of heat released into surroundings

Further explanation

Reaction

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O, the ∆H is –2200 kJ

Reaction exothermic( ∆H=-, released heat to surrounding) and for combustion of 1 mole of C3H8

So for two moles of C3H8, the enthalpy :

$\tt -2200\times 2=-4400~kJ$