Read the Introduction to Chapter 1, and Sections 1.8 and 1.9 of the textbook before viewing this slide show.

Unit 3Matter 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 to form water, neon does not react with much of 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

Solid:•Particles “close” together•Particles vibrating but not changing location•Particles very ordered

Images are screen shots from States of Matter simulationPhET Interactive SimulationsUniversity of Coloradohttp://phet.colorado.edu

Notice that as the temperature decreases the particles get closer together and move more slowly

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 ofPure Substances

• Pure substances can further be categorized as:– Elements – substances which cannot be

broken down into simpler substances by chemical means

– Compounds – chemical combination of two or more elements

Periodic table from common.wikimedia.org

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.

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