Standard State Conditions - Standard Temperature and Pressure
Know the Standard State Conditions Values of thermodynamic quantities are commonly expressed for standard state conditions, so it is a good idea to understand what the standard state conditions are. A superscript circle is used to denote a thermodynamic quantity that is under standard state conditions: ΔH = ΔH° ΔS = ΔS° ΔS = ΔS° Standard State Conditions Certain assumptions apply to standard state conditions. Standard temperature and pressure commonly is abbreviated as STP. The standard state temperature is 25°C (298 K). It is possible to calculate standard state values for other temperatures. All liquids are pure. The concentration of all solutions is 1 M (1 molar). All gases are pure. All gases are at 1 atm pressure. The energy of formation of an element in its normal state is defined as zer