Energetics Flashcards
Define enthalpy.
The total energy content of a system held at constant pressure.
Define the principle of conservation of energy.
The total energy content of the universe is constant. Energy cannot be created or destroyed.
Define allotropes.
Same element with different structural arrangement in the same physical states.
Define heat capacity.
The amount of heat required to raise the temperature of an object by a given amount.
Define specific heat capacity.
The heat capacity per unit mass of a particular substance.
Define standard molar enthalpy change of combustion.
When one mole of substance is completely burnt in oxygen under standard conditions of 298K and 1 bar.
Define standard molar enthalpy change of formation.
When one mole of compound is formed from its elements in standard states under standard conditions of 298K and 1 bar.
Define Hess’s law.
If a reaction can take place by more than one route, the overall enthalpy change is the same regardless of the route taken.
Define standard molar enthalpy change of bond dissociation.
When one mole of bonds of a particular type are broken under standard conditions of 298K and 1 bar.
Define bond enthalpy.
The energy required to break 1 mole of a specific covalent bond between 2 atoms in 1 mole of gaseous molecules.
Define average bond enthalpy.
The energy needed to break 1 mole of bond in a gaseous compound averaged over similar molecules.
Define standard enthalpy of sublimation.
The energy absorbed when 1 mole of atoms is vaporised.
Define standard enthalpy of ionisation.
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms.
Define standard enthalpy of dissociation.
The energy required to dissociate 1 mole of molecules into atoms.
Define electron affinity.
The energy required to form 1 mole of anion from 1 mole of gaseous atoms.
