Ch. 2 Matter and Change

Matter Anything that has mass and takes up space Mass –Amount of matter the object contains

Substances Matter that is uniform and has a definite composition (Pure Substances) Is sugar a pure substance? –Yes—100% sucrose Is lemonade a pure substance?

Physical Properties Quality or condition of a substance that can be observed or measured without changing the substance’s composition What are some? –Color, solubility, odor, hardness, density, melting point, boiling point

States of Matter Solids –Matter that has definite shape and volume Liquids –Form of matter that flows, has a fixed volume, and takes the shape of its container Gases –Form of matter that takes both the shape and volume of its container –Vapor—Gaseous state of a substance that is normally a solid or liquid (not interchangeable with the term gas)

Physical Changes A change which alters the material without altering the chemical composition of it –Melting of ice –Freezing of water –Water to steam –Etc etc

Mixtures Physical blend of two or more substances Like a salad! Heterogeneous mixtures –Not uniform in composition Homogeneous mixtures –Completely uniform composition Salt Water

Solutions Special name for a homogeneous mixture Solutions may be liquids, solids, or gases

Separating Mixtures Distillation –A liquid is boiled to produce a vapor that is then condensed again to a liquid –Tap Water

Elements –Simplest forms of matter that can exist under normal laboratory conditions –Cannot be separated into simpler substances –Oxygen, Hydrogen, Carbon

Compounds Two or more elements that combine together They CAN be separated into simpler substances by chemical means Water –Hydrogen and oxygen Table Salt –Sodium chloride

Chemical Symbols Represent individual elements Provide a shorthand way of writing the chemical formulas H 22 O 11C 12 H 22 O 11

Chemical Reactions One or more substances change into new substances Reactants –Starting substances Products –Substances formed Ex: Iron + Oxygen Iron Oxide (Rust)

Chemical Properties Ability of a substance to undergo a chemical reaction and to form new substances Rusting is a chemical property of iron Observed when a substance undergoes a chemical change

Law of Conservation of Mass In any physical change or chemical reaction, mass is neither created nor destroyed…..it is conserved