chem energetics Flashcards
(12 cards)
standard enthalpy change of formation
the energy change when one mole of substance is formed from its constituent elements in their standard states at 298K and 1 bar
standard enthalpy change of combustion
the energy evolved when one mole of substance is burnt completely IN EXCESS OXYGEN at 298K and 1 bar
standard enthalpy change of atomisation
the energy absorbed when one mole of gaseous atoms is formed from the element in its standard state at 298K and 1 bar
standard enthalpy change of neutralisation
energy evolved when one mole of water is formed in the reaction between an acid and a base at 298K and 1 bar
standard enthalpy change of solution
energy change when one mole of substance (in its standard state) is completely dissolved in infinite dilution in an aqueous solution at 298K and 1 bar
standard enthalpy change of hydration
energy evolved when one mole of gaseous ions is converted to one mole of aqueous ions at infinite dilution at 298 and 1 bar
lattice energy
energy evolved when one mole of an ionic sold is formed from its constituent gaseous ions (at infinite distance apart)
bond energy
average energy absorbed when one mole of a given covalent bond in a gaseous compound is broken into gaseous atoms
first ionisation energy
energy absorbed to remove one mole of electrons from one mole of gaseous atoms of an element to form one mole of singly charged positive gaseous ions
first electron affinity
energy change when one mole of gaseous atoms of an element gain one mole of electrons to form one mole of singly charged negative gaseous ions
what is entropy
the measure of disorder of a system
factors affecting entropy
- change in temperature
- change in phase (state)
- change in number of particles (especially gaseous reactants/products)
- mixing of particles
