Introducing Chemistry Chapter 2 - Matter and Change

What is Chemistry? Chemistry - Defined as the study of composition, structure, and properties of matter Matter - Has mass Takes up space Exists in four states: solid, liquid, gas, plasma

Is it matter??? Rocks Smoke Bacteria Baby powder Salt Oxygen stars Milk Mars Gravity Air Jupiter Magnetic force Light Steam Dissolved sugar Dust Rotten apples Love Electricity Heat Cells Sound waves Atoms Water Fire

Chemistry cont. Chemical – any substance that has a definite composition. Ex.) Nitrogen, Oxygen, Water, Hydrochloric acid

Classification of Matter 1. Pure substance *fixed composition *all samples have identical properties *2 kinds of pure substances 1. Elements (one type of atom) 2. Compounds (two or more types of atoms) Atom – the smallest unit of an element

Compound or Element?

Classification of Matter, cont. 2. Mixture *Blend of 2 or more kinds of matter *Each part retains its unique properties A. Homogeneous (uniform) - also called solutions B. Heterogeneous (not uniform)

Properties of Matter Physical Property *Property that can be observed/measured without altering the substance’s composition ex/ melting point, color, density Chemical Property *Property that relates to a substance’s ability to change into new/different substances ex/ability of iron to rust

Properties of Matter, cont. Extensive properties – depends on amount of matter, not type ex/ calories, mass, length Intensive properties – depends on type of matter, not amount ex/ density, melting point, boiling point

Changes in Matter 1. Physical Change *Changing matter without changing its chemical identity ex/ tear paper, phase change 2. Chemical Change (Chemical reaction) *Changing matter into a new substance *Atoms are rearranged, NOT created ex/ Fe + O2  Fe2O3

Physical Change - States of Matter Gases -Indefinite shape -Indefinite volume, compressible Liquids -Indefinite shape -Definite volume, slightly compressible Solids -Definite shape -Definite volume, incompressible Plasma

Physical change – Phase changes Solid  liquid Liquid  gas Gas  liquid Liquid  solid Gas  solid Solid  gas Melting Vaporization Condensation Freezing Deposition Sublimation

Chemical Change Chemical reaction – The final substances are chemically different from beginning substances. Reactants – substances that begin and react Products – the resulting chemicals

Evidence of a Chemical Change Color Change Odor Gas evolved Energy produced Precipitate formation

Branches of Chemistry Organic Chemistry – the study of most carbon-containing compounds Inorganic Chemistry – the study of non-organic compounds particularily metals Physical Chemistry – the study of the properties and changes of matter and their relation to energy

Branches of Chemistry Analytical Chemistry – the identification of the components and composition of materials Biochemistry – the study of substances and processes of living things Theoretical chemistry – uses math and computer to understand the principles behind chemical behavior and predict properties of new compounds

Chapter 1 Review Pg. 22 ~ 1, 3, 6-14, 17, 19-21