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?

Types of substances

• Elements • Simplest, pure substance, one type of atom present– O2, Na, Fe, N2

Elements

There are over 100 elements in the periodic table. Elements all have unique symbols:

Hydrogen: HLithium : LiOxygen : O2

Neon : Ne

Types of substances

• Compound • 1. Made of several different atoms (combined by chemical reaction)– Salt- NaCl– Sugar- C6H12O6

• 2. Different properties from the elements that make them up

Types of substances

• Mixtures • 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 Solutionsa) Alloys- solid metal

solutionsb) Gold= copper and goldc) Brass= copper and zincd) Sterling silver= silver

and copper

Types of substances

• Homogeneous Mixtures

• Solutionsa) One substance dissolved in

anotherb) Tiny particles can’t be seenc) Best mixedd) Clear or transparent- light

passes right throughe) Ocean water, lemonade, air