Chapter 3 Matter-Properties and Changes

States of Matter Solid Liquid Gas Plasma Definite shape and definite volume. Tightly packed Liquid Matter that flows; Fixed volume and no definite shape. Loosely packed, stay together as a unit. Gas No definite shape or volume. Widely spaced, free to move alone. Plasma Atoms lose their electrons and become charged particles.

States of Matter High Temperature Low Temperature Gas Liquid Solid Low Temperature Note: Any substance can be in any state at any given temperature.

Properties and Changes Physical Properties Characteristic that can be observed or measured without changing the identity of the substance. Extensive Depend on the amount of matter. Mass, volume or amount energy Intensive Doesn’t depend on the amount of matter. Boiling/Melting points, density conductivity.

Chemical Properties The actual composition of a substance. Ability of a substance to undergo chemical reactions and to form new substances.

Changes Physical Change Chemical Change Change that doesn’t involve a change in the identity of the substance. Chemical Change Change in which one or more substances are converted into different substances. Involves a chemical reaction Reactants  Products

Mixtures Consist of a physical blend of two or more substances, that retain their same internal composition. Can be separated by physical means. Homogeneous (solution) Uniform in composition, only one phase visible. Heterogeneous Not uniform throughout, two or more phases visible.

Mixtures Separations of Mixtures Distillation Filtering Crystallization Extraction Chromatography

Pure Substance Contains a fixed composition throughout. Homogenous sample of matter. Elements and Compounds Law of Definite Composition A compound has the same ratio of elements by mass, no matter how large of a sample given. H2O 11.2% Hydrogen and 88.8% Oxygen H2O2 5.9% Hydrogen and 94.1% Oxygen

Pure Substances Atoms Elements Compounds Smallest unit of an element that retains the chemical identity of the element. Elements Cannot be broken down into simpler substance. Made up of one type of atom. Compounds Can only be broken down into simpler substance through chemical reactions. Made up of two or more different atoms.

Summary

Chemical Symbols Representation of an element. One to two letters. Two letter symbols, 1st is capitalized and 2nd is lower case. Some symbols are from their Latin or German origins.

Introduction to the Periodic Table Groups (Families) Vertical columns Periods Horizontal rows

Types of Elements Metals Nonmetals Metalloids Noble gases Luster, good conductors, ductile and malleable. Nonmetals Dull, poor conductors, non-ductile and brittle. Metalloids Share traits of both metals and nonmetals. Noble gases Unreactive, “inert” gas found in group 18.

Law of Definite Composition Law of Conservation Law of Definite Composition A compound always contains the same elements in the same proportions by mass. The mass ratio of A to B will always be the same. In this case 1:3 or 25% to 75% If atoms are indivisible mass must be conserved A + B  AB +  1 a.u. + 3 a.u.  4 a.u.

Law of Multiple Proportions If two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers. CO2; 1g to 2.66g CO; 1g to 1.33g Ratio of oxygen would 2:1.

Law of Definite Proportions Calculations Hydrogen and Oxygen have a mass ratio of 1:16. What is the mass of oxygen needed to form with 14g of Hydrogen? What is the total mass of this compound?

Law of Definite Proportions Calculations Magnesium and Oxygen have a mass ratio of 3:2. What is the mass of oxygen needed to form with 20g of Magnesium? What is the total mass of this compound?