HW 12-8 Enthalpy and Stoichiometry Problem Set

2 H2 + O2 → 2 H2O ∆H = -572 kJ can also be written as: Balanced chemical equations link moles of reactants, products, and heat energy absorbed or released 2 H2 + O2 → 2 H2O ∆H = -572 kJ can also be written as: 2 H2 + O2 → 2 H2O + 572 kJ Endothermic or Exothermic? Link to egg explosion Link to explosion Eggosthermic!

Reaction Recipes can be scaled up or down 2 moles H2 + 1 mole O2 → 2 moles H2O + 572 kJ ½ x recipe: 1 moles H2 + 1/2 mole O2 → moles H2O + kJ 2x recipe: 4 moles H2 + 2 mole O2 → moles H2O + kJ 1 286 4 1144

Calculate heat released when 8.08 g H2 burns in excess O2 2 H2 + O2 → 2 H2O + 572 kJ 8.08 g H2 ( ( ) ) 1 mole H2 - 572 kJ 2.02 g H2 2 mole H2 = -1144 kJ = -1140 kJ (3 SF)

Calculate heat released when 9.50 g Al reacts with excess Fe2O3 2 Al + Fe2O3 → Al2O3 +2 Fe ∆H = -850 kJ 9.50 g Al Link to thermite Link to thermite 2 ( ) ( ) 1 mole Al - 850kJ 27.0 g Al 2 mole Al = -150. kJ (3 SF)

Link to egg explosion Link to thermite Link to thermite 2 Link to explosion