Question

Reaction 1: C3H8(g)+5O2(g)→3CO2(g)+4H2O(g), ΔH1=−2043 kJ

Reaction 2: 4C3H8(g)+20O2(g)→12CO2(g)+16H2O(g), ΔH2=?

Express your answer to four significant figures and include the appropriate units.

Answer 1

notice how reaction 2 is simply reaction 1 multiplied by 4. therefore, deltaH2 is simply 4 times deltaH1