ENVIRONMENTAL RISK ASSESSME
AND MANAGEMENT
(HES4808)
Lecture 02
DEPARTMENT OF ENVIRONMENTAL SCIENCES
UNISA
JUNE 2021
,Lesson 2
Chemicals and chemical
exposure in the environment
,Chemicals
and chemical
exposure in
the
environment
, A chemical is any substance consisting of matter (either a solid, liquid, or gas) having a consta
and properties.
Chemicals A chemical (elements, mixtures and compounds) cannot be physically separated from its com
requires the breaking of chemical bonds holding the components together.
Could change between the various states (liquid, solid, gas, plasma).
Plasma has no definite shape or volume and is electrically conductive, produces magnetic fiel
current. Plasma state does not exist under normal conditions on earth but generated by light
sparks, fluorescent lights neon lights.
Examples of chemicals include pure water, gold, Table salt, sugar etc
transitions between the four fundamental states of matter