Chemistry is the
study of the
Branches of Chemistry
•
Organic chemistry – this is the study of
compounds that are based on the element
carbon. This is the largest branch of
chemistry! All known life in the universe is
based on the element carbon!
•
Inorganic chemistry - the study of compounds
•
Physical Chemistry
- the study of the
properties and changes of matter and their
relationship to energy
•
Analytical Chemistry
– the identification of the
components and composition of materials
•
Biochemistry
– the study of substances and
What is a
substance?
A substance is matter that has a definite
composition.
The 2 types of susbstances:
Elements
An element is a substance
that contains only 1 type
of atom!
Anything listed on the
periodic table is an
Building Blocks of Matter
•
All matter is made up
of atoms. Atoms are
the smallest unit of an
element that maintains
the properties of that
element. There is only
one type of atom in
Compounds
•
A compound is a
substance that is
made of 2 or more
different atoms that
are chemically
Examples of compounds
Water, H2O, is an example of a compound
Table salt, NaCl, is a compound
Matter and Its Properties
What is matter?
Matter is anything that has mass and takes up
space!
There are 4 states of matter
•
Solids
•
Liquids
•
Gases
Properties of
Solids
Solids have the following properties:
•Definite shape •Definite volume
•Atoms or molecules are
packed close together, or dense
•Strong attractive forces
between atoms or molecules
•Atoms or molecules move
Amorphous solids
An
amorphous
solid is a
non-crystalline solid
is a solid that
Properties of liquids
Liquids have the following properties:
• No definite shape •Definite volume
•Atoms or molecules are
not packed very close together
•Weak attractive forces
between atoms or molecules
•Atoms or molecules move
faster compared to solids – they can slide past each other
Properties of Gases
Gases have the following properties:
•No definite shape •No definite volume
•Atoms or molecules are spread very
far apart
•No attractive forces between atoms
or molecules
•Atoms or molecules move very fast •They flow
Plasma
Plasma is a very high temperature form of matter where the atoms lose their electrons and become a mixture of charged particles.
Examples of plasma:
Lightning Stars
Physical properties and Physical Changes
Physical properties are characteristics that can be observed or measured without changing the identity of the substance.
Examples:
Melting point, boiling point, density,
Physical Changes:
Physical change is a change that does not change the chemical identity of the
substance. Examples:
•Change of state (Melting, boiling, freezing)
•Breaking
•Change in color
•
A bottle that shatters when
Chemical
Properties
A chemical property describes how a
substance may
undergo changes to transform into a
different substance.
Examples:
•Flammability
Chemical Changes
A chemical change is when one or more substances are converted into a different substance or substances.
This can also be called a chemical reaction.
In a chemical reaction, the substances that change are called the
reactants and the new substances created are called the products.
Example:
Signs a chemical reaction is
taking place
:
•
Color change
•
Gas is given off
•
Energy is released or
absorbed
Mixtures
•
Mixtures are a physical combination of 2 or more
substances, with each retaining its own properties.
•
Mixtures that have a uniform composition are
called homogeneous mixtures or solutions. An
example of a solution is salt water.
Substances
Both compounds and elements are considered to
be
substances.
A substance has a fixed composition.
This means that any part of a substance is exactly
like any other part of the substance
Mixtures differ
from substances
because they can
be physically
separated!!
Examples:
Filtering
Distillation
Screens
Element Symbols
Every element on the table has its own
unique symbol. If there is only one letter, it is a capitol letter.
If there are two letters, the second letter is always
Groups and Periods on the Table
The vertical columns on the table are called
groups
Types of elements
There are 3 types of elements:
•
Metals
•
Non-Metals
•
Metalloids, also sometimes called semi-metals
Properties of
Metals
• Solids, except for
mercury (Hg)
•Excellent conductors
of electricity and heat
•Most are shiny
•Malleable – can be
made into sheets
•Ductile – can be
Properties of
Non-metals
•
Can be solids,
liquids or gases
depending on the
non-metals
•
Dull
•
Excellent
insulators
Metalloids have
properties of both
metals and
non-metals
Metalloids:
Noble Gases
Elements in group 18 are also called the Noble gases. These are special because they are unreactive
elements. Helium is used for balloons, neon, argon, krypton and xenon are used in lighting.