enthalpy equations

Cards (12)

what type of reaction produces negative overall energy change?
exothermic
what type of reaction produces positive overall energy change?
endothermic
what is activation energy?
minimum energy required by reactants to react
what is enthalpy change (H)?
change in heat energy measured at constant pressure (kJmol-1)
what is an exothermic reaction?
heat energy given out from system to surroundings
what is an endothermic reaction?
heat energy taken in to system from surroundings
what are the standard conditions?
298K, 100KPa, 1moldm-3
what is standard enthalpy of formation (Hf)?
enthalpy change when one mole of compound is formed from elements, where all reactants and products are under standard conditions
in standard enthalpy of formation, what can you not change the ratio of in an equation?
products - must be 1
what is the enthalpy of formation of elements in their standard state?
0
What is standard enthalpy of combustion (Hc)?
enthalpy change when one mole of substance is burned in excess oxygen, where all reactants and products are under standard conditions
in standard enthalpy of combustion, what can you not change the ratio of an equation?
reactant – must be 1