Gas-phase ion chemistry Gas-phase ion chemistry Gas phase ion chemistry is a field of science encompassed within both chemistry and physics. It is the science that studies ions and molecules in the gas phase, most often enabled by some form of mass spectrometry. By far the most important applications for this science is in studying the thermodynamics and kinetics of reactions. For example, one application is in studying the thermodynamics of the solvation of ions. Ions with small solvation spheres of 1, 2, 3... solvent molecules can be studied in the gas phase and then extrapolated to bulk solution. Transition state theory is
Mass fraction (chemistry) Mass fraction (chemistry) In chemistry, the mass fraction formula_1 is the ratio of one substance with mass formula_2 to the mass of the total mixture formula_3, defined as The symbol formula_5 is also used to denote mass fraction. The sum of all the mass fractions is equal to 1: Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called "percentage by weight", abbreviated "wt%"; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size; mole fraction (percentage by moles, mol%) and