3. INTRODUCTION
The measurement of a physical property may
change the arrangement of matter in a sample,
but not the structure of its molecules. In other
words, a physical property may involve
a physical change, but not a chemical
change.Examples of physical properties include
mass, density, color, boiling point, temperature,
and volume.
14. Chemical change
occur when a substance combines with another to
form a new substance, called synthesis or,
alternatively, decomposes into two or more different
substances. These processes are called chemical
reactions and, in general, are not reversible except by
further chemical reactions.
15. Condesation apparatus
In a laboratory a condenser is a piece
of laboratory glassware used to cool hot vapors
or liquids. [1] A condenser usually consists of a
large glass tubecontaining a smaller glass tube
running its entire length, within which the hot
fluids pass.
The ends of the inner glass tube are usually
fitted with ground glass joints which are easily
fitted with other glassware. During reflux, the
upper end is usually left open to the
atmosphere or vented through a bubbler or
a drying tube to prevent the ingress of water or
oxygen.[2]
16. WHAT IS A ATOM? HISTORY…
• the study of the atomic nature of matter
• A unit of matter, the illustrates the thinking process that goes on
in the philosophers and scientists heads. The
smallest unit of an element, models they use do not provide an absolute
understanding of the atom but only a way of
consisting of a dense, abstracting so that they can make useful
predictions about them. The epistemological
central, positively charged methods that scientists use provide us with
the best known way of arriving at useful
nucleus surrounded by a science and factual knowledge. No other
method has yet proven as
system of electrons, equal successful.Actually, the thought about
electricity came before atoms.
in number to the number of • In about 600 B.C. Thales of Miletus
discovered that a piece of amber, after
nuclear protons rubbing it with fur, attracts bits of hair and
feathers and other light objects. He
suggested that this mysterious force came
from the amber. Thales, however, did not
connect this force with any atomic particle.
