energetics

Cards (8)

what is enthalpy? 
the heat energy change at a constant pressure
what kind of reaction will have a positive enthalpy value?
endothermic
what kind of reaction will have a negative enthalpy value?
exothermic
what are the conditions for measuring enthalpy?
standard conditions -100kPa and 298K
what is the enthalpy change of formation?
the enthalpy change when 1 mole of a compound is formed from its constituent elements in standard conditions, with all products and reactants in their standard state
what is the enthalpy change of combustion?
the enthalpy change when 1 mole of a compound is burnt completely in oxygen under standard conditions and all reactants and products are in standard states
what is hess' law?
the enthalpy change for a reaction is independent of the pathway taken
what is mean bond enthalpy?
the enthalpy change to break 1 mole of a bond, average over a range of compounds