define and use the terms: (a) standard conditions (this syllabus assumes that these are 298 K and 101 kPa) shown by \(^\circ\). (b) enthalpy change with particular reference to: reaction, \(\Delta H_r\), formation, \(\Delta H_f\), combustion, \(\Delta H_c\), neutralisation, \(\Delta H_{neut}\)

use the terms mole fraction and partial pressure