A thermochemical equation is a stoichiometric question that now involves the variable of ΔHReaction. Instead of doing a mole to mole comparison we will now do a mole to ΔH comparison.
Concept #1: Understanding Thermochemical Equations
Example #1: Iron is reacts with oxygen according to the following equation at around 2000oC. (0:35 – 4:10)
4 Fe (s) + 3 O2 (g) → 2 Fe2O3 (s)
ΔHo = + 65.2 kJ/mol
Calculate the amount of grams of iron (III) oxide, Fe2O3, produced from the absorption of 4.82 x 109 J.
Practice: Nitromethane (CH3NO2), sometimes used as a fuel for drag racing, burns according to the following reaction: 4 CH3NO2 (l) + 7 O2 (g) -----> 4 CO2 (g) + 6 H2O (g) + 4 NO2 (g) ?H = ? 2441.6 kJ How much heat is released by burning 125.0 g of nitromethane (MW: 61.044 g/mol)?