Chem Energetics Flashcards
standard 🔺H of formation definition
energy change when 1 mol of a substance in its standard state is formed from its constituent elements in their standard states, at a specified temperature, usually 298K
standard 🔺H of combustion definition
energy released when 1 mole on a substance is completely burnt in excess O2, w all reactant and products in their standard states, at a specified temp, usually 298K
standard 🔺H of neutralisation definition
energy released when 1 mole of water is formed in the neutralisation between an acid and base in standard states, at a specified temperature, usually 298K
bond energy definition
average energy required to break 1 mole of a covalent bond between 2 atoms in gaseous state
Hess’ Law
🔺H of a reaction is determined only by its initial and final states and is independent of the reaction pathway taken
standard 🔺H of atomisation (element)
energy required to form 1 mole of gaseous atoms from the element, all in their standard states, at a specified temperature, usually 298K
standard 🔺H of atomisation (compound)
energy required to form gaseous atoms from the 1 mole of the compound, all in their standard states, at a specified temperature, usually 298K
lattice energy
energy released when 1 mole of solid ionic compound is formed from its constituent gaseous ions
ionisation energy
energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of singly charged gaseous cations
electron affinity
energy change when 1 mole of electrons is added 1 mole of gaseous atoms to form 1 mole of singly charged gaseous anions
standard 🔺H of hydration
energy released when 1 mole of free gaseous ions in its standard state is dissolved in water to give a solution of infinite dilution, at a specified temperature, usually 298K
standard 🔺H of solution definition
energy change when 1 mole of substance in its standard state is completely dissolved in a solvent to give a solution of infinite dilution at a specified temp, usually 298K
entropy definition
measure of the randomness/disorder in a system, reflected in the no. of ways the energy can be distributed through the motion of its particles
