Introduction to Chemical Engineering Processes/Notation

A Note on Notation Base Notation (in alphabetical order) : Molarity of species i in stream n a, b, c, d: Stoichiometric coefficients. A: Area C: Molar concentration (mol/L) K: Equilibrium coefficient m: Mass MW: Molecular Weight (Molar Mass) n: Moles n: Number of data points (in statistics section) N: Number of components P: Pressure r: Regression coefficient R: Universal gas constant T: Temperature v: Velocity V: Volume x: Mole fraction in the liquid phase OR Mass fraction Unless specified explicitly, assume that a given percent composition is in terms of the overall flowrate. So if you're given a flowrate in terms of kg/s and a compositoin of 30%, assume that the 30% is a mass fraction. If a given equation requires one or the other, it will explicitly be stated near the equation which is necessary. X: (molar) extent of reaction y: Mole fraction in the gas phase z: Overall composition Z: Compressibility Greek : Density : Sum Subscripts If a particular component (rather than an arbitrary one) is considered, a specific letter is assigned to it: [A] is the molarity of A is the mass fraction of A Similarly, referring to a specific stream (rather than any old stream you want), each is given a different number. is the molar flowrate in stream 1. is the molar flow rate of component A in stream 1. Special subscripts: If A is some value denoting a property of an arbitrary component stream, the letter i signifies the arbitrary component and the letter n signifies an arbitrary stream, i.e. is a property of stream n. Note is the molar flow rate of stream n. is a property of component i. The subscript "gen" signifies generation of something inside the system. The subscripts "in" and "out" signify flows into and out of the system. Embellishments If A is some value denoting a property then: denotes the average property in stream n denotes a total flow rate in steam n denotes the flow rate of component i in stream n. indicates a data point in a set. is a property of pure component i in a mixture. Units Section/Dimensional Analysis In the units section, the generic variables L, t, m, s, and A are used to demonstrate dimensional analysis. In order to avoid confusing dimensions with units (for example the unit m, meters, is a unit of length, not mass), if this notation is to be used, use the unit equivalence character rather than a standard equal sign.