Enthalpy Flashcards
What is the definition of average bond enthalpy?
The energy required to break one mole of a specific type of bond in a gaseous molecule.
Describe bond breaking and bond making
Bond breaking= When energy is required to break bonds, this takes in heat and is endothermic
Bond making= when energy is released when bonds are formed, this is exothermic.
What does conservation of energy mean?
A rule that states that energy cannot be created nor destroyed
Equation for energy?
Q = mcAT
(A represents triangle for change in temp)
What are the standard conditions?
Standard pressure = 100Kpa ( equivalent to one atmosphere)
Standard temperature = 298K
Standard concentration = 1 mole dm^-3
Standard state= physical state of substance under standard conditions
Definition of standard enthalpy change of reaction
The enthalpy change which accompanies a reaction in molar quantities shown in a chemical equation under standard conditions with all reactants and products in their standard states.
Definition of standard enthalpy change of formation
Enthalpy change that takes place when one mole of a compound is formed from its elements under standard conditions with all reactants and products in their standard states.
Definition of standard enthalpy change of combustion
Enthalpy change that takes place when one mole of a substance reacts completely with oxygen under standard conditions.
Definition of enthalpy change of neutralisation
The energy change that accompanies reaction of an acid by a base to form one mole of H2O under standard conditions.
Definition of specific heat capacity
Energy required to raise the temperature of 1g of a substance by 1K
What does Hess’ Law state?
States that if a reaction can take place by two routes and both start and finish in the same conditions then the total enthalpy change would be the same for each route.
What is the definition of lattice enthalpy?
Enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions.
Define Standard enthalpy change of atomisation
The enthalpy change that takes place for the formation of one mole of gaseous atoms from an element in its standard state under standard conditions, this is always endothermic because bonds are broken to form gaseous atoms.
Definition of first ionisation energy
The enthalpy change required to remove one electron from each atom in one mole of gaseous atoms you form one mole of gaseous 1+ ions.
What is the definition of first electron affinity?
Enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of 1- ions.
