Mass transfer is the phrase commonly used in engineering for physical processes that involve molecular and convective transport of atoms and molecules within physical systems. Mass transfer includes both fluid flow and separation unit operations. In general, a molecule is the smallest particle of a pure chemical substance that still retains its composition and chemical properties. ... Convection is the transfer of heat by currents within a fluid. ... Properties An atom (Greek άτομον from ά: non and τομον: divisible) is a submicroscopic structure found in all ordinary matter. ... In general, a molecule is the smallest particle of a pure chemical substance that still retains its composition and chemical properties. ... A system is an assemblage of inter-related elements comprising a unified whole. ... This article or section should be merged with Fluid mechanics Fluid dynamics is the study of fluids (liquids and gases) in motion, and the effect of the fluid motion on fluid boundaries, such as solid containers or other fluids. ... Unit operation is the basic principle of chemical engineering. ...

Some common examples of mass transfer processes are the evaporation of water from a pond to the atmosphere; the diffusion of chemical impurities in lakes, rivers, and oceans from natural or artificial point sources; mass transfer is also responsible for the separation of components in an apparatus such as a distillation column. Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ... Water (from the Old English word wæter; c. ... Layers of Atmosphere (NOAA) Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... Schematic drawing of the effects of diffusion through a semipermeable membrane. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... The Murray River in Australia. ... The worlds oceans as seen from the South Pacific Ocean (from Okeanos, Greek for river, the ancient Greeks noticed that a strong current flowed off Gibraltar, and assumed it was a great river); covers almost three quarters (71%) of the surface of the Earth, and nearly half of the... Strathisla whisky distillery in Keith, Scotland Distillation is a method of separation of substances based on differences in their vapor pressures. ...

In astronomy, mass transfer is the process by which matter gravitationally bound to a body, usually a star, fills its Roche lobe and becomes gravitationally bound to a second body, usually a compact object (white dwarf, neutron star or black hole), and is eventually accreted onto it. It is a common phenomenon in binary systems, and may play an important role in some types of supernovae, and pulsars. Lunar astronomy: the large crater is Daedalus, photographed by the crew of Apollo 11 as they circled the Moon in 1969. ... Matter is commonly defined as the substance of which physical objects are composed. ... It has been suggested that this article or section be merged into gravity. ... STAR is an acronym for: Scientific and Technological Advanced Research Labs, a fictional research organization in the DC Comics universe. ... The Roche lobe is the region of space around a star in a binary system within which orbiting material is gravitationally bound to that star. ... White dwarf Sirius-B in x-rays A white dwarf is an astronomical object which is produced when a low or medium mass star dies. ... Neutron stars are one of the few possible endpoints of stellar evolution. ... For any questions on black holes see Black hole FAQ A black hole is a concentration of mass great enough that the force of gravity prevents anything from escaping it except through quantum tunnelling behaviour (known as Hawking Radiation). ... A binary star system consists of two stars both orbiting around their barycenter. ... Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ... Composite Optical/X-ray image of the Crab Nebula pulsar, showing surrounding nebular gases stirred by the pulsars magnetic field and radiation. ...