Physical and Chemical Changes Unit II—Part 2

Concept of Change Change: the act of altering a substance

Physical Change Physical change: a change that occurs that does not change the identity of the substance Melting ice Freezing Kool-aid Tearing paper Dissolving sugar in water

Chemical Changes Chemical change: a change that occurs causing the identity of the substance to change Burning Digesting food Rusting A chemical change is called a chemical reaction

Chemical Changes Cont’d Indicators of a chemical change: Production of light Production of heat Production of a gas Color change Formation of a precipitate

Is it Physical or Chemical? Glass breaking

Is it Physical or Chemical? Burning leaves 7

Is it Physical or Chemical? Butter melting 8

Is it Physical or Chemical? Fireworks exploding 9

Is it Physical or Chemical? Pouring milk on cereal 10

Is it Physical or Chemical? Mowing a lawn 11

Is it Physical or Chemical? Separating sand and gravel 12

Is it Physical or Chemical? Bleaching hair 13

Is it Physical or Chemical? Frying an egg 14

Is it Physical or Chemical? Hammering nails into wood to frame a house 15

Is it Physical or Chemical? Burning toast 16

Is it Physical or Chemical? Mixing powdered Kool-Aid with water 17

Is it Physical or Chemical? Adding salt to water to gargle 18

Is it Physical or Chemical? Food spoiling 19

Is it Physical or Chemical? Rusting bicycle 20

Is it Physical or Chemical? Melting ice cream 21

Changes Physical Chemical

Describing Matter

What is Matter? What is a Substance?

Properties of Matter Substance: Single kind of pure matter with a specific makeup and set of properties. 1. Physical Property: Characteristic of a pure substance that can be OBSERVED without changing it into another substance. Helps you identify/classify/describe matter ie: Density, hardness, texture & color

What are some Physical Properties?

2. Chemical Properties Characteristic of a pure substance that describes its ability to change into different substances because of its composition. CAN’T be observed by looking or touching ie: a. IRON reacts with oxygen to form RUST… a completely different/new substance. b. SILVER reacts with sulfur in the air to form TARNISH.

What was the substance before and what did it become? Burning produces new products…heat, gas and ashes

Properties Physical Chemical