A2 - Enthalpy And Hesses Cycle Flashcards
Definition of bond enthalpy
Energy needed to break one mile of covalent bonds in the gaseous state
What is endothermic
Where bonds are broken
Energy is required so taken in
🔼H is positive
What is exothermic
Energy is released
Bonds are made
🔼H is negative
Definition of an exothermic reaction
The enthalpy of the products is lowers than the enthalpy of the reactants energy is released
Definition of endothermic reaction
Enthalpy of the products is higher than the enthalpy of the reactants energy is absorbed
What are the standard conditions of
Temperature
Pressure
Solution concentration
Temp - 25 degrees
Pressure - 1atm or 100kPa
Solution - 1moldm3
What is the standard enthalpy of reaction
The heat energy change at constant pressure when the amounts of reactants under standard conditions to give the products in their standard states
Definition of standard enthalpy of formation
Enthalpy change when one mole of a compound is formed in its standard state from its constituent elements in their standard states in standard conditions
Definition of standard enthalpy of combustion
The enthalpy change when one mole of a substance in its standard state reacts completely with oxygen under standard conditions
Definition of standard enthalpy of neutralisation
Enthalpy change when 1 mole of water is formed from the reaction of an acid with a base
Definition of bond enthalpy
Enthalpy change when 1 mole of a given type of bond is broken in the gaseous state
