Elements, Compounds & Mixtures

GOAL • To tell the difference between elements, compounds and mixtures and to give examples of each

Matter

• Matter is anything that has mass and takes up space.

• Matter is made up of many different things:

Substance

A substance is a single kind of matter that has a specific composition and a specific set of properties - for example, color, melting point, texture . . .

Physical Properties

Physical Properties are characteristics of substances that can be observed without changing it into another substance.

Examples: freezing or melting density hardness color

Chemical Properties

Chemical Properties are characteristics of pure substances that describe their ability to change in to different substances.

Chemical Properties

Examples: Does it burn? (Flammability) Does it combine with oxygen?

(Iron does and forms rust.) What will the substance react with?

• Elements Types of substances •

Simplest, pure substance, one type of atom present

–

O 2 , Na, Fe, N 2

Elements

There are over 100 elements in the periodic table. Elements all have unique symbols: Hydrogen: H Lithium : Li Oxygen : O 2 Neon : Ne

Types of substances • Compound • 1. Made of several different atoms (combined by chemical reaction) – Salt- NaCl – Sugar- C 6 H 12 O 6 • 2. Different properties from the elements that make them up

• Mixtures Types of substances • 1. Made of more than one kind of molecule (many compounds) • 2. Can be separated or pulled apart by physically (they are NOT chemically combined) • 3. 2 types: – Heterogeneous – Homogeneous

Heterogeneous Mixtures • You can see the different parts.

• Examples: • Salad • Soil • Bowl of Mixed Nuts

Types of substances • Heterogeneous Mixtures • 1. Not the same throughout • 2. Large easily seen particles that can be separated out • 3. Heterogeneous liquid mixtures known as suspensions – Settles after standing • 4. Tacos, salad, italian dressing, pebble/sand mixture

Homogeneous Mixture • They are so evenly mixed, you can not see the individual parts.

• Examples: • Salt dissolved in water • Brass is a mixture of copper and zinc

Types of substances • Homogeneous Mixtures • 1. Appears same throughout • 2. Well mixed • 3. Won’t settle upon standing, • 4. Tiny unrecognizable particles – Solutions are homogeneous mixtures

Types of substances • Homogeneous Mixtures – Won’t settle out – Cloudy-Scatters light – Particles mix, don’t dissolve • Milk, lotion, toothpaste

Types of substances • Homogeneous Mixtures • Metal Solutions a) Alloys- solid metal solutions b) Gold= copper and gold c) Brass= copper and zinc d) Sterling silver= silver and copper

Types of substances • Homogeneous Mixtures • Solutions a) One substance dissolved in another b) Tiny particles can’t be seen c) Best mixed d) Clear or transparent light passes right through e) Ocean water, lemonade, air