enthalpy

• enthalpy


  • total energy associated with a system at a constant pressure
  • measure it as enthalpy change /_\H
  • change in enthalpy= change in enthalpy of products-change in enthalpy of reactants
• • exothermic reactions= negative enthalpy change value, heat energy is given out
  • endothermic reactions= positive enthalpy change value, heat energy absorbed
• calculating enthalpy changes


  bond enthalpies

  • enthalpy change= sum of bonds broken- sum of bonds formed