-
Lecture 2 & 3
General Knowledge
of Chemistry
Index
Chemistry Glossary
Atoms
Compounds
Elements
Formulas
Molecules
Periodic Table
Acids and Bases
Gases
Ions
Liquids
Solids
Mixtures
Physical and Chemical
Changes
An Introduction
Chemistry is the science of matter -
what matter is like, what makes up matter, what
changes
occur in matter, what causes
those changes. It is key to all the other sciences
and a part of
every aspect of our
world
.
Chemistry
Glossary
Word
adhesion
alloy
anion
atom
a mixture of
metals
an ion with a
negative charge.
The
smallest particle of an element.
Definition
the
force or attraction that holds two separate
objects together.
atomic
the total number of protons and
neutrons in an atom.
mass/weight
atomic
number
brittleness
catalyst
cation
chemical
bonds
chemistry
cohesion
colloid
compound
the
number of protons in the nucleus of an atom as
well as the number of
electrons in a
neutral atom.
the property
of matter that is how easily the substance breaks
or shatters
when force is applied to
it.
a substance that helps
along a chemical reaction or change without being
changed itself.
an ion with a positive
charge.
the process by which
atoms combine to form molecules.
The science of matter and the changes
in matter.
the attraction
that holds together the molecules within one
substance.
a mixture in
which the substance is split into tiny particles
and spread within
a second es include
smoke and fog.
a substance
made up of two or more elements that are combined
chemically.
to
become smaller, closer together
thickness of a substance
when a substance spreads out within
another substance as when a solute
spreads out within a solvent in a
solution, sometimes unevenly.
property of a metal in which it can be
stretched without breaking.
the ability of a substance to be
stretched and then to return to its original
shape.
a form of
energy coming from charges.
a particle of the atom that has a
negative charge. The electron is not a part
boiling point
temperature at which a liquid changes
to a gas.
concentration
the
amount of a solvent compared to the solute in a
solution.
contract
density
diffusion
dissociation
separation of a substance into atoms or
ions.
ductility
elasticity
electricity
electron
of the
nucleus, but moves around in an orbit around the
nucleus.
element
a substance made of one kind of atom
that cannot be broken down
chemically.
endothermic
When heat is
given off curing a chemical reaction.
reaction
energy
exothermic
reaction
formula
hardness
heat
inorganic
chemistry
ion
isotope
light
liquie
the
ability to do work or make change.
When heat is absorbed during a chemical
reaction.
tells what
chemicals a compound is made up of
property of matter that determines how
easily the substance can be
scratched.
a form
of energy marked by differences in
temperatures
the study of
chemical elements and compounds except for carbon.
an atom or group of atoms
that have a net electrical charge
atoms with the same number of protons,
but different numbers of neutrons.
visible electromagnetic
radiation
a state of matter
that has a definite size or volume but not a
definite shape.
evaporation
changing of a liquid to a vapor at any
temperature below its boiling point.
malleability
the
property of a metal that allows it to be hammered,
rolled, pressed or
forged.
melting point
the
temperature at which a substance changes from a
solid to a liquid.
mixture
molecule
nucleus
neutron
organic
chemistry
several
substances put together that can be easily
separated by physical
means.
the smallest particle of a substance
that still is that substance.
the center of the atom consisting of
the proton and neutron.
a
particle in the center of the atom with no
charge.
the study of the
compounds of carbon.
periodic table
A
chart of all the elements arranged by atomic
number.
periodic
table
chart of the elements
arranged in columns and rows according to the
increasing atomic numbers.
property
proton
a
characteristic of matter such as color, density,
brittleness, etc..
a
particle in the center of the atom that has a
positive charge.
radioactivity
the
breakdown or decay of the nucleus of an atom by by
the emission or
giving off of
particles.
solution
sound
a mixture
of two or more in which two or more materials are
dissolved in
another
material.
a disturbance that
travels through air, land, water that can be
heard.
sublimation
the
changing of a gas directly to a solid.
suspension
similar to a solution, but the
particles within the suspension can be seen by
the naked eye.
temperature
measure of how warm or cold a substance
is.
tensile
strength
the
resistance of a substance to any force used to
tear it apart.
Atoms
An atom is the smallest particle of an
element that still is that element.
The atom is made up of several parts.
It has a center part called the nucleus. The
nucleus is
made up of a positively
charged particle called a proton and a particle
that does not have a
charge
called
a
neutron.
The
nucleus
is
surrounded
by
negatively
charged
particles
called
electrons that move in orbits around
the nucleus. Most of the mass of the atom is
contained in
the
nucleus
and
the
mass
of
the
proton
and
neutron
are
about
the
same.
However,
the
nucleus is a small portion of the total
amount of space the atom takes up. Different types
of
atoms can be identified by the
numbers of protons, neutrons and electrons they
contain and
their atomic
mass.
Atoms
that
have
the
same
number
of
protons
but different
numbers
of
neutrons are
called
isotopes.
The negatively charged electrons are
very light in mass. An atom is described as
neutral if it
has an equal number of
protons and electrons or if the number of
electrons is the same as the
atomic
number of the atom. The electrons that are
outermost can combine with other atoms
by giving up or taking on electrons.
This can cause atoms to have an electrical charge
and
these
kinds
of
atoms
are
called
ions.
Atoms
can
also
share
electrons
and
this
is
called
a
chemical
bond.
The atomic number of
an atom is the number of protons it has. The
atomic weight or mass of
the atom is
the total number of protons and neutrons in the
atom's nucleus.
Compounds
A
compound
is a
substance
made
up
of
two
or more
elements
combined
chemically.
This
combination is similar to a recipe for
a dessert in which one combines the different
ingredients
in specific amounts to one
another to create a delicious treat!
Compounds
are
made
up
of
elements
which
are
a
kind
of
atom
or
of
a
combination
of
compounds.
When
they
are
combined
chemically,
it
is
very
difficult
to
separate
out
the
different elements just as it is very
difficult once a cake is baked to separate out the
eggs, flour,
sugar and other
ingredients.
Compounds often
have common names such as water or salt - but are
also named by their
formula which tell
what elements make up the compound and in what
proportion. For example,
the smallest
bit of water, a molecule of water, is made up of
two hydrogen atoms for every one
oxygen
atom. A formula is similar to a very precise
recipe for a compound.
Compounds are made up of many, many
molecules of that compound.
Elements
An
element
is
made
up
of
one
kind
of
atom
and
cannot
be
broken
down
into
any
simpler
substance
chemically.
To
break
down
an
element
would
take
much
more
sophisticated
means. This
would break the element down into subatomic
particles.
Elements
have
both
physical
and
chemical
properties.
Physical
properties
of
elements
are
color, density (how thick the element
is), how much it might conduct electricity and
heat as
well as the boiling and melting
points.
Elements
are
often
classified
by
these
properties
into
groups
called
families.
One
set
of
groupings is whether the elements are
metals, non-metals or metalloids. Other groups
include
the inert gases, halogens, and
alkali metals.
All the
elements are arranged on the Periodic Table of the
Elements, starting with those with
the
smallest
atomic
weights
to
those
with
the
largest.
They
are
also
arranged
in
columns
within the table
with those having similar properties being in the
same column.
Each element
has its own symbol consisting of one or two
letters.
Formulas
Formulas tell what makes up a compound.
They show a chemical reaction and are written like
a math equation. The smallest particle
of a compound would be a molecule of that
compound.
One of the best
known formulas is the formula for water. Water is
made up of two different
elements,
hydrogen and oxygen. One molecule of water is made
up of two atoms of hydrogen
and one
atom of oxygen. The symbol for hydrogen is H and
the symbol for oxygen is O. The
formula
for water would be H2O. If there is only one atom
in the formula, no number is affixed
to
the symbol.
Some formulas
are simple and some are very complex.
Some formulas can be stated several
ways. The molecular version tells the exact
composition
of a molecule of the
compound. An empiracal formula gives a simpler
version that is rather
like a reduced
fraction. For example:
Molecular formula for glucose:
C6H12O6
Empiracal formula
for glucose: CH2O
Molecules
A molecule is the smallest part of a
substance called a compound that still is that
substance.
For example, a molecule of
water is the smallest bit of water that still is
water. A molecule of a
substance
cannot
be seen
by
the
naked
eye
-
a
drop of
water is made up
of
many,
many
molecules of water.
Molecules
are
composed
of
atoms
joined
together
chemically.
Molecules
do
not
have
an
electrical charge.
Scientists believe
that
molecules are
always
moving.
They
can
be
solids,
liquids
or gases.
Molecules
move
the
most
and
are
the
furthest
apart
when
they
are
gases.
Molecules
are
closest together and
move the most slowly when they are solids.
Molecules that are liquids
movement is
between those of gases and those of
solids.
A formula tells what
elements make up a molecule. For example, a
molecule of water is made
up of two
hydrogen atoms and one oxygen atom. The formula
for a molecule of water is H2O.
Molecules
come
in
different
sizes
and
molecular
weights.
Their
atoms
can
be
arranged
in
different ways. Molecules in substances
can be split up in chemical reactions to form
other
molecules. They
can
also
recombine
into
larger molecules or be broken down
into
smaller
molecules,
Periodic Table
The
Periodic
Table
is
a
chart
featuring
all
the
elements.
It
was
put
together
by
Dmitri
Mendeleev. He set up
the chart by organizing the the elements according
to the physical and
chemical properties
they have in common, Each grouping is arranged
starting with those with
the lowest
atomic number and moving along in order of these
atomic numbers. The groups
are
numbered
from
one
to
eight
in
Roman
numerals
(I-VIII).
Each
group
is
split
into
two
subgroups called families. These
families are called the a series and the b
series.
All the elements in
the same group are similar chemically. They have
the same number of
valence electrons.
Valence is the ability of different atoms to form
chemical bonds based on