INTRODUCTION TO CHEMISTRY
Specific learning objectives
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Define Chemistry
Explain Chemistry as a Science
Mention the branches of Chemistry
Highlight the career opportunities in Chemistry
List the apparatus in the Chemistry laboratory
Meaning of Chemistry
Chemistry is the science of the composition, properties, structure, and uses of matter as
well as the changes associated with matter.
Chemistry as a Science
Science as an organized body of knowledge adopts some steps in the course of an
inquiry. This process of inquiry is known as the Scientific Method or Scientific
Approach. It begins with an observation and ends with a law as shown below. Hence
the reason Chemistry is a science.
Observation
Hypothesis
Experiment
Theory
Law
To make observations means to state the problem and collect data. Observations may be
qualitative or quantitative. A qualitative observation does not involve a number. For
instance, colour and state of matter (solid, liquid, gas). A quantitative observation is a
measurement and does involve a number and a unit. An observation is something that
is witnessed and can be recorded.
To formulate hypothesis means to provide a possible explanation for the observation.
To perform experiments means to test the hypothesis.
During experimentation, new information is gathered which enables decision on
whether the hypothesis is supported by the new information learned from the
experiment. Experiments always produce new observations and this starts or initiates
the process of inquiry as depicted above.
To explain the behaviour of a given part of nature, the first three steps (observation,
hypothesis, experiment) are repeated many times and gradually knowledge necessary
to understand things accumulate. Once a set of hypotheses agrees with the various
observations, they are assembled into a theory.
A theory is a set of tested hypotheses that gives an overall explanation of some parts of
nature. Theories are human inventions. They represent human attempts to explain
observed natural behaviour in terms of human experiences. A theory is an
interpretation – a possible explanation of why nature behaves in a particular way.
Theories inevitably change as more information becomes available. This implies that
questions will continue to be asked about nature even after explaining the behaviour of
nature; experiments will continue to be conducted to refine theories. This is done by
using the theory to make a prediction and then doing experiments (making a new
observation) to see whether the results bear out this prediction. Scientists must continue
to do experiments and refine theories to be consistent with new knowledge if we hope
to approach a more nearly complete understanding of nature.
As scientists observe nature it is noticed the same observation applies to many different
systems. For example, studies of a large number of chemical changes have shown that
the total mass of materials involved is the same before and after the change. Such
generally observed behaviour is formulated into a statement called law. The
observation that the total mass of materials is not affected by a chemical change in those
materials is called the law of conservation of mass.
Differences between a law and theory
A law is a summary of observed behaviour whereas a theory is an explanation of
behaviour.
A law tells what happens; a theory is a human attempt to explain why it happens.
What type of science is Chemistry?
Chemistry is a pure science because its inquiry is carried out in a laboratory.
Branches of chemistry
Physical Chemistry is the branch that deals with the structure of matter and how
energy affects it.
Inorganic Chemistry is the branch that deals with the study of elements, their
compounds and their chemical reactions.
Organic Chemistry is the study of carbon compounds with the exception of its oxides,
sulphides, carbonates and hydrogen carbonates.
Analytical Chemistry is the branch concerned with the techniques used to identify and
quantify the composition of matter.
Industrial Chemistry is the branch concerned with the methodology and other related
aspects of commercial preparation of various compounds.
Environmental Chemistry is concerned with natural and synthetic substances in the
environment and their impact on the environment.
Career Opportunities in Chemistry
Chemistry as a science has paved way for numerous careers such as Biochemist,
industrial chemist, environmental chemist, food chemist, clinical chemist, petroleum
chemist, chemical engineer, pharmacy, subject teacher in a college, lecturer in a higher
institution among other careers.
Familiarization of laboratory apparatus in the Chemistry laboratory
Name of
apparatus
Description
Use of apparatus
Test tube
It is made of glass
and available in
various sizes.
It is used to perform
chemical tests and
to boil the solutions
Boiling tube
It is made of hard
glass (pyrex) and
wider than a test tube
It is used for strong
heating
Diagram
Beakers
It is a cylindrical
glass container
containing a beak at
the upper side. It is
available in various
volumes such as 1
000 cm3 , 600 cm3, 500
cm3, 250 cm3, 100 cm3
It is used to pour
liquid from one
container to another
Filter Funnel
It is made of glass
(glass funnel) or
plastic (plastic
funnel). It is conical
in shape with a
hollow tube. It is
available in various
sizes.
It is used for
filtration and
sublimation.
It is cylindrical in
shape with graduated
marks. It is made of
glass or plastic and
available in various
volumes
It is used to the
measure specific
volume of liquid
Erlenmeyer flask
It is made of glass
and conical in shape.
It is available in
various volumes such
as 100 cm3, 250 cm3,
500 cm3 and 1000 cm3
It is used in
volumetric analysis
Round bottom
flask
It is made of glass
and possesses a
round bottom
It is used in the
preparation of gases
Measuring
cylinder
Flat bottom flask
It is made of glass
and possesses a flat
bottom.
It is used in the
distillation process.
Volumetric flask
It is made of corning
glass. Its upper part
is cylindrical while its
lower part is conical.
It is available in
various volumes such
as 100 cm3, 250 cm3,
500 cm3, 1000 cm3
and 2000 cm3
It is used in the
preparation of
standard solutions
It is a hollow
cylindrical tube made
of glass. It has
graduated marks on
it. The lower portion
possesses a glass tap
or rubber tube with a
cork. A normal
laboratory burette
has a volume of 50
cm3
It is used in
volumetric analysis
as a measuring
apparatus
Burette
Pipette
Retort stand
Wire gauze
Tripod stand
It is a thin hollow
cylindrical tube
having cylindrical
bulb at the middle
portion. It is available
in various volumes
such as 1 cm3, 10 cm3,
20 cm3. 25 cm3
It is used in
volumetric analysis
It is made of cast
iron. It has a
rectangular base
fitted with a vertical
rod. A clamp can be
adjusted on the rod
with a screw
It is used to hold on
to materials that
require support
It is a flat iron mesh
with a sheet of
It is used to support
asbestos paper
the beaker and other
trapped at its centre
glass container
so that the glass
during heating over
container do not
a bunsen burner
come in direct contact
with flame and crack
It is made of cast
iron. It is triangular
in shape fitted with
three rods for
support.
It is used to support
during heating
Test tube stand
Test tube holder
Test tube brush
Wash bottle
Bunsen burner
Mortar – pestle
Beehive shelf
It is made of plastic
or wood.
It possesses an iron
strip fitted in a
cylindrical wooden
base.
It is made of thick
and hard iron wire
with plastic bristles
It is used to keep
and support test
tubes
It is used to hold
test tubes during
heating
It is used for
cleaning test tube
It is made of plastic
and contains a thin
tube
It is used for
washing and rinsing
glass apparatus.
It is a heating device
made of metallic base
and a gas inlet tube
fitted with a brass
nipple
It is used for heating
They are made of
porcelain. The mortar
is a thick walled
vessel, hemispherical
in shape and possess
a base
It is made of
porcelain. It has holes
at upper and lower
part to insert the
delivery tube
The mortar is used
for grinding salts
and other
substances with the
help of pestle.
It is used for the
collection of a gas in
a gas jar
It is used to hold
small samples of
powdered
substances
Watch glass
It is a circular, curveshaped transparent
glass container
Spatula
It is made of metal or
plastic
Stirring rod
It is a solid rod made
of hard glass
China dish
Evaporating dish
Made of porcelain
and hemispherical in
shape
It is used for
crystallization
It is made of glass
and available in
various volumes.
Some are transparent
while others are
amber (brownish) It
has a small opening
which is capped by
glass or plastic
stopper
It is used to store
reagent
Crucible
It is made of
porcelain and has a
lid
It is used to heat
solids to high
temperatures
Clay triangle
It is made of ceramic
and appears as an
equilateral triangle
with hollow sides
through which are
drawn wires
It is used to support
crucible during
heating
It is a machine with
centrifuge tubes
It is used to separate
mixtures composed
of insoluble solids
in a solution
Reagent bottle
Centrifuge
It is used to take
chemicals from a
container
It is used for stirring
or mixing solution
Kipp’s
Apparatus
(Gas generator)
It is made of glass
and consists of three
vertically stacked
columns
It is used for the
production and
intermittent supply
of gases
Dropper bottle
with dropper
The bottle is made of
glass with plastic
dropper
It is used to hold
and dispense
liquids or solutions
required in drops
Pasteur pipette
(Droppers
or
Dropping pipette
It is made of glass or
plastic
It is used to transfer
small quantity of
liquids or solutions
required in drops
Reagent shelf
It is made of wood
It is used to store
reagents
Separating
funnel
It is made of glass
It is used to separate
immiscible liquids
It is made of glass
It is used to transfer
gases from point of
production to that
of collection
Delivery tube
Pneumatic
trough
It is made of glass
It is used to hold
water while
collecting gases
Stopper
It is cylindrical in
shape and made of
wood or rubber
It is used for sealing
the opening of the
flask
Desiccator
It is a sealable
enclosure that
contains desiccants
and made of glass
It is used to dry
solids
They are scissors –
like with two pincers
They are used to
grasp ot crucible
They are scissors –
like with two pincers
coated with rubber
They are used to
grasp hot beakers
It is a long handled
spoon with a lid
It is used t lower
burning objects into
glass vessel filled
with a gas
Crucible tongs
Beaker tongs
Deflagrating
spoon
Liebig condenser
Nichrome wire
It is made of glass
It is used to cool and
with a straight inner
condense hot vapoir
tube surrounded by a
during distillation
large outer jacket
It is an alloy of nickel
It is used in flame
or chromosome or
testing
sometimes iron
Analytical
balance
It is a very sensitive
instrument with a
draft shield
(weighing chamber)
It is used to
accurately measure
mass
Gas jar
It is made of glass
and consist of a broad
base and a broad
opening
It is used for
collecting gases