The Science of Matter

Chemistry 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

Views of matter macroscopic submicroscopic 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

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

Anything that has mass and volume Matter Anything that has mass and volume Physical changes Mixtures Physically combined Pure substances Chemically combined Chemical changes Elements Compounds Heterogenous mixtures Homogenous mixtures

MIXTURES Heterogeneous mixtures Homogenous 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

PURE SUBSTANCES elements compounds Simplest form of matter – made up of one kind 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 (H2O) (C12H22O11) Examples are water and sugar

Types of Properties Physical Properties… Chemical 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.

Types of Changes Physical Changes Chemical 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. © 2009, Prentice-Hall, Inc.