Standard Conditions for enthalpy changes
100KPa
Speciefied temp (298K)
What is the standard enthalpy of formation
The enthalpy change when 1 mole of the compound is for,ed form its elements in standard states and conditions
What is the standard enthalpy of combustion
The enthalpy change when 1 mole of a substance is completely burned in oxygen under standard conditions
What is the standard enthalpy of neutralisation
The enthalpy hange when an acid and an alkali react to form 1 mole of water under standard conditions
What is bond breaking
Endothermic
What is bond making
Exothermic
Equations for enthalpy changes
q=m c deltaT
M=volume in grams
Delta T= change in temp
q= heat lost or gained in joules
DeltaH = q/n
Remember to add in positive or negative sign at the end
Describe what is meant by activation energy
The minimum amount of energy particles must collide with in order for the reaction to occur
Describe a Exothermic graph
Reactants higher than products
Activation energy from reactants to top of hill
Delta H from reactants to products
Describe an endothermic graph
Reactants lower then products
Activation energy from reactants to top of hill
Delta H from reactants to products
Define enthalpy change
The heat added to the system under constant pressure
Enthalpy change = enthalpy of products- enthalpy of reactants
Describe the Hess cycle for enthalpies of formation
Y shape both arrows come from elements to reactants/products
Times given values by molar quantity
Describe Hess cycle for enthalpy of combustion
Both arrows come into the intermediate
take into account molar quantities
Describe Hess cycle for bond enthalpies
Both arrows come into the intermediate
