 The science that investigates and explains the structure and properties of matter  Structure refers to its composition —what matter is made up of and how it is organized  Properties describe the characteristics and behaviors of matter

MACROSCOPICSUBMICROSCOPIC  Large enough to be seen  One you touch, feel, smell, taste, and see  So small that you cannot see it even with the most powerful microscope

A thinking device that helps you understand and explain macroscopic observations  Can be a drawing  Computer generated  Built on experimentation

Matter Anything that has mass and volume Mixtures Pure substances Physical changes Heterogenous mixtures Homogenous mixtures ElementsCompounds Chemical changes

HETEROGENEOUS MIXTURESHOMOGENOUS MIXTURES  Different compositions, depending upon where you look  Components exist as distinct regions called phases  Examples are orange juice and graphite  Constant composition throughout  No matter where you sample the mixture, you find the same combination  Another name is a solution  Examples are sugar water and air

ELEMENTSCOMPOUNDS  Simplest form of matter  Cannot be broken down into simpler substances  Building block from which other forms of matter are made  Examples are found on the periodic table  A chemical combination of two or more different elements joined together in a fixed proportion  Properties of compound is different from the properties of the elements it is made up of  Represented by a formula (H 2 O) (C 12 H 22 O 11 )  Examples are water and sugar

© 2009, Prentice-Hall, Inc. Physical Properties… – Can be observed without changing a substance into another substance. Boiling point, density, mass, volume, etc. Chemical Properties… – Can only be observed when a substance is changed into another substance. Flammability, corrosiveness, reactivity with acid, etc.

© 2009, Prentice-Hall, Inc.  Physical Changes These are changes in matter that do not change the composition of a substance.  Changes of state, temperature, volume, etc.  Chemical Changes Chemical changes result in new substances.  Combustion, oxidation, decomposition, etc.