Warm-Up 8/29/16 What are the two classes of matter? A(n) _______ is made up of only one type of atom. A(n) ______ contains a fixed ratio of elements. What are the two types of mixtures?
States of Matter
States of Matter Plasma: highest energy state. Gas: No definite volume, no definite shape, least dense Expands/contracts to fill container Capable of being compressed Particles are always in motion Liquid: Definite volume, no definite shape Takes the shape of container Movement is less restricted, particles move around and collide with each other Solid: Definite volume & shape Lowest energy state, most dense state (except water) Very little particle movement
Gas Terms Gases: gaseous state at room temp. Ex: H2, He, CO2, CH4 Vapor: liquid or solid at room temperature. Ex: Br2 Steam: vapor specific to water.
Phase Changes State Changes are Physical Changes Melting: Solid Liquid Freezing: Liquid Solid Vaporization: Liquid Gas Condensation: Gas Liquid Sublimation: Solid Gas Deposition: Gas Solid State Changes are Physical Changes
Phase Changes
Exothermic v. Endothermic Exothermic: Feels hot, energy exits system. http://whenchemistsattack.com/tag/exothermic- reactions/ Endothermic: Feels cold, energy enters system.
Physical Changes Physical: A change that does not change the composition of a material, observed or measured property Intensive Physical Property: Does NOT depend on size of sample. Ex: Density, boiling point, conductivity Extensive Physical Property: depends on size of sample. Ex: mass, volume
Chemical Changes Chemical: substance changes into new substance - composition changes. The substance is no longer the same, different identity (Ex. Burning) Indicators of a chemical change: Energy is absorbed/released—temperature change Change in color Change in odor Production of a gas (bubbles, fizzing)
Practice
Classify each change as either chemical or physical. Gasoline in your engine burns as you start the car. Distilled water Rust on a nail Glow sticks Medicine crushed into a powder Chemical Physical physical