Corneal Ulcer Guide: 1  Definition. 2  Causes & Prevention. 3  Diagnosis and Tests. 4  Symptoms and Signs. 5  Treatment & Prognosis. >>> 6  Dog Health A-Z.
Standard Temperature and Pressure (STP) Standard Temperature and Pressure (STP) is defined as 0 degrees Celsius and 1 atmosphere of pressure. Do not confuse STP with the STP Products Company, a maker of oil and fuel additives...unless you are reading one of their MSDS's!
This means that the change in enthalpy under such conditions is the heat absorbed (or released) by the material through a chemical reaction or by external heat transfer. Enthalpies for chemical substances at constant pressure assume standard state: most commonly 1 bar pressure. Standard state does not, strictly speaking, specify a temperature (see standard state), but expressions for enthalpy generally reference the standard heat of formation at 25 Â°C.