Changes in Matter
Types of Changes: Two Types of Changes Physical Change Chemical Change
Physical Change: Does not change the chemical composition or the nature of a substance Process is easily reversible Ex. Crumpling & smoothing out paper Ex. Freezing water and thawing ice Ex. Sublimation – from solid to gas (ex. dry ice (CO2) or iodine)
Key Words: Crush/Pulverize Melt Evaporation Condensation Sublimation Tells you a physical change occurred Key Words: Crush/Pulverize Melt Evaporation Condensation Sublimation Solidification Dissolve
Chemical Changes: Changes the chemical composition or make-up of the substance New substances are formed with new properties Not easily reversible (Reversible only through chemical means or reactions) Rust
Signs of Chemical Changes: Tells you a chemical change occurred Signs of Chemical Changes: Formation of a gas Formation of a precipitate Change in color Production of heat &/or light Increase or decrease in mass
Examples: Physical Change Chemical Change Sublimation Freezing Condensation Evaporation Pulverization (crush) Solidification Dissolving Chemical Change - Burning - Neutralization - Combustion Corrosion (rusting)
Ex #1: 1. Melting Butter 4. Crushing Rock 2. Rusted Car Which of the following are examples of physical changes? 1. Melting Butter 4. Crushing Rock 2. Rusted Car 5. Condensation 3. Dissolving Sugar in Tea 6. Burning Wood
Ex #2: 1. Cooking an egg 4. Freezing Rain 2. Rotting food Which of the following are examples of chemical changes? 1. Cooking an egg 4. Freezing Rain 2. Rotting food 5. Burning a candle 3. Sublimation of Dry Ice 6. Crumpling Paper
Ex #3: Chemical Change Physical Change Where did a chemical change occur? A physical change? You carry out the following steps of an experiment & record your observations. Ex #3: 1. You place a powder in a test tube 2. You heat the test tube. You notice that a colorless gas & a copper- colored liquid are produced. 3. You collect the copper-colored liquid & cool it. It becomes a solid. Chemical Change Physical Change
Activities: Physical Science Worksheet #2 Student Study Guide – Mod 1-14 - 1-16