energetics

• entropy is a measure of disorder
• entropy sign is S
• entropy is worked out by products-reactants
• gibbs free energy is the energy available to do work in a system
• gibbs symbol is G
• gibbs equation is G=H-TxS/1000
• gibbs: positive value means the reaction is not feasible
• gibbs: to work out temperature do T=H/(S/1000)
• lattice enthalpy is energy released when 1 mole of a solid crystal lattice is formed from its constituent gaseous ions
• enthalpy of atomisation is the energy required to form 1 mole of gaseous atoms
• electron affinity is energy exchanged when 1 electron is added to 1 mole of gaseous atoms
• enthalpy of solution is when 1 mole of a solid is completely dissolved in water
• enthalpy of hydration is the energy released when 1 mole of gaseous ions are completely dissolved in water forming 1 mole of aqueous ions
• factors affecting lattice enthalpy are the magnitude of charge, and distance between ions(smaller=closer together=stronger attraction)
• factors affecting enthalpy of hydration are ionic radius , ionic charge