More chemistry!!!?

Question

Many cigarette lighters contain liquid butane, C4H10(l). Using enthalpies of formation, calculate the quantity of heat produced when 3.7 g of butane is completely combusted in air.

=______kJ

Answer 1

C4H10 + 13/2 O2 ----> 4 CO2 + 5 H2O

Hf C4H10 = -125.5 kJ/mol
Hf CO2 = -393.5 kJ/mol
Hf H2O = -285.8 kJ/mol

delta H = 4 (-393.5) + 5 (-285.8) - (-125.5) = -2877.5 kJ/mol

3.7 g of butane is 0.0638 moles, so the energy produced is 183.6 kJ.

Answer 2

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