Galactic Plane

the plane which passes through the centre of the MILKY WAY, as far as that can be determined.

Taken from Dictionary of Science

________

The plane in which the disk of the Milky Way Galaxy lies. By definition, one direction perpendicular to this plane is called above or north, and the opposite direction, also perpendicular to the galactic plane, is called below or south. From Earth, due galactic north is marked by the north galactic pole, which lies in Coma Berenices, near the bright star Arcturus, and due galactic south is marked by the south galactic pole, which lies in Sculptor.

Taken from The Internet ENCYCLOPEDIA OF SCIENCE

Qualitative Analysis

the chemical examination of a sample to discover what substances are present.

Taken from Dictionary of Science

___________________________________________________________

In the qualitative analysis procedure, the chemical properties of an unknown substance are determined by systematically reacting the unknown with a number of different reagents. By predetermining what the particular reaction will produce if a specific ion is present, the ions that actually are in the solution can be identified. For example, if a reaction is known to produce a precipitate if ion A is present and a precipitate is formed when the reaction is run, then ion A may be present in solution (there may be, and usually are, other ions that will also precipitate with a particular reagent). If no precipitate is formed when the reaction is run, then ion A is clearly not present in the unknown solution and a different reaction will have to be run to determine what ions are present.

There are two general situations in which qualitative analysis is used - in the identification of a simple salt, or the identification of multiple cations in a solution.

Taken from Wired Chemist