Section 2.1

The Nature of Matter

What Are We Made Of?

What are little boys made of? What are little boys made of? Frogs and snails and puppy-dogs' tails, That's what little boys are made of.

What are little girls made of? What are little girls made of? Sugar and spice and all that's nice, That's what little girls are made of.

Section 2.1

The Nature of Matter

Objectives

1. To learn about the composition of matter

2. To learn the difference between elements and compounds

3. To define the three states of matter

Section 2.1

The Nature of Matter

The Composition of Matter

• Empedocles, 492-432 B.C. a Greek philosopher thought that matter was made up of four elements:

• Democritus, 460 – 370 B.C. viewed matter as being made of atomos but he had no way of testing his hypothesis. That had to wait for another 2000 years….

Section 2.1

The Nature of Matter

A. The Particulate Nature of Matter

• Matter has mass and occupies space. • It is composed of tiny particles called atoms.

One atom of aluminum is about 0.000000000000000000000003 cubic centimeters in volume

Section 2.1

The Nature of Matter

B. Elements and Compounds

Elements

• Elements contain only one type of atom – elemental copper contains only copper atoms and elemental gold contains only gold atoms.

What other elements occur, as pure elements, in nature?

Section 2.1

The Nature of Matter

B. Elements and Compounds

Compounds

• Compounds are substances that contain two or more different types of atoms in a specific ratio.

How does the ratio of C to O in different samples of carbon monoxide differ?

Section 2.1

The Nature of Matter

Atoms and Molecules

• An Atom is the smallest particle that an Element can be divided into without losing its identity

• A Molecule is the smallest particle that a Compound can be divided into without losing its identity

But you will also hear O2, H2, N2 etc. referred to as molecules

Section 2.1

The Nature of Matter

C. The States of Matter

• Matter exists in three states:– Solid: a rigid substance with a definite shape – Liquid: has a definite volume but takes the shape of its

container – Gas: takes the shape and volume of its container

How do the volumes of solid, liquid and gaseous water compare? What is in between the molecules?

Section 2.1

The Nature of Matter

Where else are transitions between states of matter important?

1912 Titanic Sinks