Glossary of Terms

• Salt

  An ionic compound made up of a cation and an anion. It is often produced in neutralizaion reactions.

• Scientific Notation

  A systematic way of expressing a number in exponential notation. The format is

  #.### x 10 #

• Semimetals

  Also called metalloids, are elements that have both metallic and nonmetallic properties.

  These are:

  • B, Si, Ge, As, Sb, Te, Po, At

  The semimetals are positioned next to the diagonal line on the periodic table, between the metals, and the nonmetals.

• SI unit

  The system of units used universally for expressing all measured quantites is Le Système International d'Unités (The International System of Units). Some SI units are:

  Physical quantity	Units	Symbol
  length	meter	m
  mass	kilogram	kg
  time	second	s
  temperature	kelvin	K
  energy	joule	J
  charge	coulomb	C

• Standard Temperature and Pressure (STP)

  standard temperature is 273 K (or 0 oC).
  standard pressure is 1 atm (760 torr)

• Substance

  A substance has constant composition and properties throughout. All substances are either elements or compounds.

• Titration

  A procedure used to determine the concentration of a solution by a chemical reaction with a solution of accurately known concentration. This is achieved by a gradual addition of the solution of accurately known concentration until the indicator gives a visual colour change that signals that the chemical reaction between the two solutions is complete.

• Units

  The units of a measurement indicates the standard against which the measured quantity is compared. In Chemistry, the units for:
  
  • length is meter
  • mass is gram
  • volume is liter

• Valence electrons

  The electrons in the outermost energy level of an atom. The number of valence electrons vary from 1 to 8. These are the electrons that participate in chemical bonding.

• Vector

  Vectors are quantities that can be described when both their magnitude and direction are specified. Examples of vectors are velocity, force and momentum.

  Dipole moment is also a vector quantity.

• Work

  In science, work is a measure of the transfer of energy. It is expressed as a force acting through a distance.

  work = (force) x (distance)

  The unit of work can be in joules or calories.

Rosamaría Fong, Instructor of Chemistry,
British Columbia Institute of Technology, Burnaby, B.C. Canada.

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All contents copyrighted © 1996
Rosamaría Fong, Instructor of Chemistry
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