How many kilojoules of heat are produced when 6.39 mol of Al react? 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s) heat of reaction = –851.5 kJ

Before it was launched, a helium-filled balloon had a pressure of 201 kpa at a temperature of 27°c. at an altitude of 15,000 m, the pressure had decreased to 2.5 kpa and the temperature had dropped to -14 °c. the volume of the balloon increased to 59.3 m3. what is the original volume of the balloon? 13 m3 0.85 m3 0.077 m3 1.17 m3