Energetics Flashcards
What is enthalpy change
heat or energy change under constant pressure
What is the equation for energy change
energy change= mass x specific heat capacity x temp change
What is hess law
The enthalpy change for a reaction is independent of the the route taken
What is Enthalpy change of formation
Enthalpy change when 1 mole of a compound is formed from is constituent elements in their standard state and under standard conditions
Enthalpy change of formation arrows go
upwards
how to workout bond enthalpy
Reactants - products both in positive form
What is enthalpy change of combustion
Enthalpy change when 1 mole of a compound is burned completely in oxygen when all reactants and products are in their standard state and under standard conditions
What is enthalpy change of combustion
Enthalpy change when 1 mole of a compound is burned completely in oxygen when all reactants and products are in their standard state and under standard conditions
Enthalpy change of combustion arrows go
downwards
Enthalpy of atomisation/bond enthalpy
When 1 mol of gaseous atoms are formed from an element in their standard state
Enthalpy of 1st ionisation
when 1 mol of gaseous +1 ions are formed from 1 mol of gaseous atoms
Enthalpy of electron affinity
When 1 mol of gaseous -1 ions are formed from 1 mol of gaseous atoms
Enthalpy of lattice formation
when 1 mol of solid ionic compound is formed from its from its gaseous ions
Enthalpy of lattice dissociation
When 1 mol of solid ionic compound separates into its gaseous ions
Enthalpy of hydration
when 1 mol of aqueous ions is formed from 1 mol of gaseous ions
Enthalpy of solution
When 1 mol of solute is dissolved in enough solvent so that no further enthalpy change occurs in further distillation
bond dissociation
When a covalent bond is broken into 2 gaseous atoms
When does covalent character occur
Relatively small ion has high positive charger, relatively larger ion with high negative charge bond together
Equation for gibs free energy
Gibs free energy= enthalpy change-(Temp(K) x entropy)
Calculate entropy
Entropy of products- entropy of reactants
