An Example…:
An Example… CH 4(g) + 2O 2 (g) CO 2 (g) + 2H 2 O + 890. kJ q r = -890. kJ Heat of reaction is based on the number of moles given in the balanced equation If the amount of moles change, the q r changes
Mass – Energy Problems:
Mass – Energy Problems Similar to Mass-Mass problems, except your mole-mole ratio is now a mole-energy ratio For the methane burning example, your mole-energy ratio for the CH 4 would be
Practice Problem:
Practice Problem How much heat is generated by the reaction of 1.99 g Na 2 O 2 with water? 2 Na 2 O 2 + 2 H 2 O 4 NaOH + O 2 + 215.76 kJ
Practice Problem:
Practice Problem 2 Na 2 O 2 + 2 H 2 O 4 NaOH + O 2 + 215.76 kJ Given the equation above, if 300.0 kJ of energy are produced, what mass of Na 2 O 2 reacted?