Enthalpy

• an open system can exchange matter and energy with its surroundings.
• an closed system allows the transfer of energy but no matter with its surroundings.
• an isolated system cannot exchange matter or energy with its surroundings.
• enthalpy is a measure of the chemical potential energy stored in a system. The enthalpy changes as chemical bonds and intermolecular forces change during a reaction. This results in a heat transfer which can be observes
• reactive stability determines if reaction is endo or exo
• lowering energy increases the stability
• endothermic reactions occur when there is an increase in the dispersal of the system
• the minimum KE to react is known as the Ea
• the standard enthalpy change when 1 mole of a compound is formed from its elements in their standard states at room temperature and pressure.