Unit 3
Matter and Its Transformations
•What is chemistry? (Introduction to Chapter 1)
•Physical and chemical properties (1.8)
•Physical and chemical changes (1.8)
•Classification of matter (1.9)
What is Chemistry? (Intro to Chapter 1)
• Matter – anything that occupies space and has a
mass (1.8)
• Chemistry – the study of matter and its
transformations (Introduction to Chapter 1)
Physical and Chemical Properties
(1.8)
• Physical property – a physical characteristic or
behavior of the material
– Examples: boiling point, hardness, color
• Chemical property – describes how the
material reacts with (or doesn’t) with other types
of matter
– Examples: iron rusts in moist air, hydrogen and
oxygen react violently, neon does not react with
anything
Physical and Chemical Changes (1.8)
• Physical change – a change in the appearance
of a substance without changing its chemical
identity or composition
– Examples: melting ice, cutting a piece of wood in half
• Chemical change – a change in the chemical
identity of matter into other substances that are
different
– Examples: hydrogen and oxygen react to form water,
a piece of iron rusts,
Classification of Matter (1.9)
• With over 18 million characterized compounds,
categorization is important to provide a
framework for study
• This initial classification system provides a good
starting point
• As you might imagine, there are
subclassifications under many of these basic
groupings
States of Matter (1.9)
• Three common states of matter (plus a bonus):
– Gas – takes shape of container, flows easily,
compressible
– Liquid – takes shape of container but with a flat top,
flows easily, not very compressible
– Solid – retains shape, does not flow appreciably, not
very compressible
– (A bonus state: plasma – a stream of charged particles
– this is the stuff of plasma TV)
Particle Level Description of States of Matter
Gas:
•Particles “far” apart
•Particles moving
rapidly
Liquid:
•Particles “close”
together
•Particles moving slowly
•Particles more ordered
than gas, but not as
much as solid
Notice that as the temperature
decreases the particles get closer
together
Solid:
•Particles “close”
together
•Particles only vibrating
•Particles very ordered
Images are screen shots from States of Matter simulation
PhET Interactive Simulations
University of Colorado
http://phet.colorado.edu
Pure Substances and Compounds (1.9)
• Pure substance – has a definite fixed
composition that does not vary from one sample
to another
– Examples: pure copper, pure water
• Mixture – variable composition that can be
different from one sample to another
– Examples: salt water, air, sand and water mixed
together
Further Classification of Pure Substances
• Pure substances can further be categorized as:
– Elements – substance which cannot be
broken down into simpler substances by
chemical means
– Compounds – chemical combination of two or
more elements
Periodic Table – the elements
A sample periodic table - if it’s a known element it is on here.
Compounds are chemical combinations of multiple elements. A large
portion of our course will be involved with studying the periodic chart.
Periodic table from common.wikimedia.org
Further Classification of Mixtures
• Mixtures can further be categorized as:
– Homogeneous – all parts of the mixture have
the same composition and appearance
• Examples: sugar dissolved in water, air, a “pinch”
of salt dissolved in water
– Heterogeneous – appearance is not the same
throughout
• Examples: sand in water, oil in water
Summary of Classification of Matter
Matter
Pure
Substances
Elements
Compounds
Mixtures
Homogeneous
Mixtures
Heterogeneous
Mixtures