1. Chapter 15 Classification of Matter

2. Sec. 1 Composition of Matter All materials are either made of pure substances or mixtures. Substance—an element or compound. Element—a substance with atoms that are all alike Ex. Carbon (C) & Magnesium (Mg) Ex. Carbon (C) & Magnesium (Mg) You can find them on the periodic table!! You can find them on the periodic table!! Compound—a substance that contains 2 or more elements combined chemically. Ex. Table salt (NaCl) & Hydrogen peroxide (H 2 O 2 ) Ex. Table salt (NaCl) & Hydrogen peroxide (H 2 O 2 )

3. Mixtures Mixture—a material made of 2 or more substances that can be separated physically. There are 2 types of mixtures: heterogeneous and homogeneous. Heterogeneous Mixture—different materials can be distinguished easily. Ex. Pizza, salad, chocolate chip cookies (mmm) Ex. Pizza, salad, chocolate chip cookies (mmm) Homogeneous Mixture—substances are blended evenly throughout. Ex. Pop, vinegar Ex. Pop, vinegar A homogeneous mixture is also called a solution. A homogeneous mixture is also called a solution.

4. Colloids & Suspensions Colloid—a type of mixture that never settles. Ex. Paint & fog Ex. Paint & fog A colloid is not the same as a solution Colloids often appear foggy Colloids often appear foggy If you shine a light on a colloid, you can see the light reflected from the colloid. If you shine a light on a colloid, you can see the light reflected from the colloid. Suspension—a heterogeneous mixture containing a liquid in which visible particles settle. Ex. Mud in a pond & river deltas Ex. Mud in a pond & river deltas

6. Sec. 2: Properties of Matter Physical Properties—any characteristic of a material that you observe without changing its substances. Ex. Color, shape, size, melting & boiling point Ex. Color, shape, size, melting & boiling point Some physical properties describe behavior. Magnetism, conduct electricity, viscosity, dissolving. Magnetism, conduct electricity, viscosity, dissolving. You can separate mixtures using physical properties. Size, color, magnetism, etc. Size, color, magnetism, etc.

7. Physical Changes/Chemical Properties Physical change—a change in size, shape, or state of matter (solid, liquid, gas) The identity of the substance doesn’t change. The identity of the substance doesn’t change. Ex. Freezing, ripping, folding, dissolving. Ex. Freezing, ripping, folding, dissolving. Chemical Property—a characteristic of a substance that tells if it can undergo a certain chemical change. Ex. Flammability, reaction to light Ex. Flammability, reaction to light

8. Chemical Properties & Changes Chemical Change—a change of 1 substance to another. Ex. Rotten eggs, rust, burning. Ex. Rotten eggs, rust, burning. Detecting Chemical Changes: Odor, heat, light, sound, release gas (bubbles), Odor, heat, light, sound, release gas (bubbles), Separating Substances: Ex. Cleaning tarnished silver, purifying metals. Ex. Cleaning tarnished silver, purifying metals. A chemical change will change the substances, so it cannot be used to separate a mixture. A chemical change will change the substances, so it cannot be used to separate a mixture.

9. Weathering Weathering is how Earth’s surface changes. Weathering is a result of both physical & chemical changes. Physical: ice wedging (ice in cracks expands & breaks the rocks), & streams cut through softer rock. Chemical: limestone dissolves in acidic ground water (canyons & caves are formed this way)

10. Conservation of Mass Law of Conservation of Mass—the mass of all substances before a chemical or physical change equals the mass of all substances after the change. In other words: mass is neither created or destroyed during any chemical or physical change.