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How much energy (in kJ) will be released if 5.00 x 10^2 g of heptane undergoes combustion?
2 Answers
- DifferentialLv 65 years ago
Heptane is C7H16, and weighs 100 g/mol. 500 g is 5 mols, which would burn to produce 35 moles of CO2 and 40 moles of H2O (gas).
Total Energy released is -{35*[hf, CO2] + 40*[hf, H2O(g)] - 5*[hf, C7H16]}
hf, CO2 = -393.5 kJ/mol
hf, H2O (g) = -241.8 kJ/mol
hf, C7H16 = -44.9 kJ/mol
Total energy released = 23,220 kJ
- 5 years ago
Es = E/m
m * Es = E
Es for Heptane is -48.1 MJ / kg
-48.1 * 10^(6) J / (10^3 g)
-48.1 * 10^(3) J/g
500 * 10^(2) * (48.1 * 10^(3)) Joules =>
500 * 10^(2) * 48.1 kJ =>
5 * 48.1 * 10^(4) kJ =>
240.5 * 10^(4) kJ =>
2.405 * 10^(6) kJ
