Glossary of Terms

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

The following is a summary of some of the base units in the SI system. All base units except the kilogram are now defined by physical phenomena which can be measured anywhere in the universe. The kilogram is still defined by a unique artifact.

Base Unit	Origin
meter (m)	The distance light travels in a vacuum in 1/299 792 458 of a second.
kilogram (kg)	The mass of the International Prototype Kilogram, a small cylinder of platinum-iridium preserved in a vault in France.
second (s)	The duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom (at a temperature of 0 K).
kelvin (K)	The fraction 1/273.16 of the thermodynamic temperature of the triple point of water.

Standard Temperature and Pressure (STP)

standard temperature is 273 K (or 0 ^oC).

standard pressure is 1 atm (760 torr)
Stoichiometry
Calculations that deal with the amounts of substances that are used up and produced during a chemical reaction. The stoichiometric ratio of the substances are obtained from the balanced chemical equation.
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.

All contents copyrighted © 1996-2006
British Columbia Institute of Technology
Chemistry Department - 3700 Willingdon Avenue
Burnaby, B.C. Canada V5G 3H2

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

Salt

Scientific Notation

Semimetals

SI unit

Standard Temperature and Pressure (STP)

Stoichiometry

Substance

Titration

Units

Valence electrons

Vector

Work