2. 1: The Nature of Matter Objectives: * To learn about the composition of matter * To learn the difference between elements and compounds * To define the three states of matter

A. THE PARTICULATE NATURE of MATTER Matter: anything that has mass and takes up space Stars, air, chair, cake, brain tissue…

The Atomic Nature of Matter -All matter consists of ATOMS Why can’t we see the atoms? Think about the beach… The sand looks uniform but as we get closer we can see all of the tiny particles

Although objects in the macroscopic world typically look uniform, they are really particulate in nature- they are made of atoms!!! We can only see them with powerful electronic microscopes

B. ELEMENTS and COMPOUNDS *Matter is composed of tiny particles called ATOMS! Atom= fundamental unit of which elements are made All matter is composed from about 100 different types of atoms

Analogy… Think of the matter in the universe like the words in a book. We can construct thousands of words with just 26 letters. The matter in the universe is constructed by about 100 types of atoms together in different ways. 100 types of atoms= the ELEMENTS of the universe

Examples: A D M MAD DAM DAD MADMA

Examples with Elements H O H2O2 H20

Compounds Just as letters combine to form different words, ATOMS combine to form different COMPOUNDS. Compounds: *2 or more different types of atoms bound together in a particular way *Always contains atoms of different elements

Some common compounds Atom Combinations Name Characteristics Carbon monoxide poisonous gas Carbon Dioxide breathe it out, plants use it to make oxygen Water most important liquid on Earth Hydrogen Peroxide disinfect cuts, bleach hair,

Molecule -Made up of atoms that are stuck together “A collection of atoms bonded together that behave as a unit.”

The molecules in water are different from the molecules in dry ice (solid carbon dioxide) A glass of water contains millions of tiny water molecules (H2O) packed closely together Dry ice contains molecules(CO2) packed closely together

Elements *Substances that contain only one type of atom Pure gold= only gold atoms Iron= only iron atoms Copper= only copper atoms

C. THE STATES OF MATTER Solid: Substance with a fixed shape and volume Liquid: Substance with a definite volume that takes the shape of its container Gas: Substance with no definite shape or volume

What happens to food coloring when we add it to water? How do our observations support the idea that water is made up of moving molecules?

Review Questions 1. How do atoms, compounds, and elements differ? 2. Use the (letters) ‘elements’ in “CHEMISTRY” to make as many word ‘compounds’ as you can. How is an element different from a compound? 3. Draw an “atom” picture of a solid, liquid, and a gas. Describe the essential differences among them.