Classifying

States of Matter

Solid Particles have a strong attraction and orderly arrangement Particles tightly packed together Definite shape and volume Expands when heated incompressible

Solid expanding when heated

What’s happening At room temperature, the atoms in the ball vibrate but do not move past each other When the metal ball is heated, the atoms vibrate faster. Their motion competes with their attractions and the move a little further apart

Liquid Attractions between particles are not as strong as in solids Randomly arranged and slightly further apart Definite volume but not a definite shape Fluid in shape and takes the shape of the bottom of a container Incompressible Expands when heated Thermometer

Gas Particles can move freely in all directions (randomly) Particles are very far apart and the attractions between them are weak No definite volume or shape (take the shape of the container) Diffuse to fill container Easily compressed

Water Vapor

Gas vs Vapor Gas Vapor Substance in the gaseous state at room temperature Example: Oxygen Gaseous state of a substance that is solid or liquid at room temperature Example: water vapor

Summary

Classification of Matter

Separate Physically Separate Chemically

Pure Substance Matter that has a constant composition and distinct properties Differ from one another in composition

Element Substance that cannot be separated into simpler substances Most occur naturally on Earth (118 to date)

Atom Molecular Smallest particle of an element that retains all properties of the element Two or more atoms chemically bonded together as a discrete unit (molecule) from only 1 type of element

Polyatomic Diatomic Molecules with only 2 atoms Ex: hydrogen, oxygen, nitrogen, chlorine, bromine, iodine, fluorine Molecules with more than 2 atoms Ex: Ozone, Sulfur, phosphorus

**First letter in ALL chemical symbols are ALWAYS capitalize, second letter is ALWAYS lowercase

Compound Substance composed of atoms of two or more elements chemically bonded in fixed proportions Has properties different than its components Can be separated by only chemical means into components (electricity & heat) Add definition!!

Ionic Molecular Compound held together by ionic bonds Ex: table salt (sodium chloride, NaCl) Compound held together by covalent bonds Ex: water, carbon monoxide

Mixture Combination of two or more pure substances in which each pure substance retains its individual identities Do not have fixed proportions Can be created or separated by physical means

Homogeneous Composition of the mixture is the same throughout Also called a solution Mixed at the molecular level and has a single phase Ex: Air, brass

State of resulting Solution Component 1 Component 2 State of resulting Solution Examples Gas *air Liquid soda *mist Solid Pop rocks, *foam alcohol Salt water, *sea water Brass, steel *Pollution

Heterogeneous Does not have uniform composition and the individual substances remain distinct Different components are visible

Chemical Formula Expresses the composition of substances in terms of their chemical symbols Subscripts denote number of atoms Mg3N2 Mg3(PO4)2 Numbers outside of the parentheses get multiplied in Add definition!!