Matter And Measurement INTRODUCTION

MATTER Substance Mixture Element Matter Compound Homo- geneous Mixture Hetero- geneous Mixture Physical Separation Chemical Separation Classification of Matter

Anything that occupies space (has volume) and has mass

Matter that has a uniform and definite composition Substances have distinctive characteristic (identifying) physical & chemical properties Elements & compounds are substances examples

A substance that can not be broken down to simpler substances by chemical means Most elements are composed of individual atoms (some elements are composed of groups of identical atoms).

A substance composed of two or more elements A compound can be broken down (decomposed) by chemical means In compounds, elements are chemically bonded

A physical blend of two or more substances Homogeneous Mixture Heterogeneous Mixture A mixture which is uniform and has a single phase (single state); also called a solution A mixture which is NOT uniform and usually has more than one phase example

MIXTURE (Example  Saltwater)MIXTURE Physical blend of substances Physical properties of mixture are the same properties of its components Components combine in any ratio Separation is by physical process Chemical combination (bonding) of 2 or more elements Physical properties of compounds are unique & different from properties of its elements Components (elements) combine in a definite ratio Separation (decomposition) is a chemical process Comparison of Mixture & Compound COMPOUND (Example  Water)COMPOUND

H 2 (g) and O 2 (g) Hydrogen Gas + Oxygen Gas H 2 O (g) Water Vapor (steam)

Extensive properties Intensive properties Volume Mass Energy Content (think Calories!) : depend on the amount of matter that is present. : do not depend on the amount of matter present. Melting point Boiling point Density Properties of Matter

CLASSIFICATION OF MATTER Salt Salt Water AirSoil Blood

CLASSIFICATION OF MATTER Sand Water Concrete Iron Brass (copper & zinc)

PHYSICAL changes Will alter a substance without changing its composition Are frequently reversible Properties or characteristics do not change Will alter a substance by changing its composition Are not frequently reversible New substances formed have new properties or characteristics Substances can be altered by Physical Changes or Chemical Changes CHEMICAL changes Examples

PHYSICAL changes Dissolving Evaporating Freezing Sodium + chlorine  NaCl silver metal gas salty taste, white, H 2 O soluble explosive in water “green” color non flammable toxic toxic non toxic CHEMICAL changes Examples

CHEMICAL CHANGE In every chemical reaction, one or more of the following can be observed When a chemical reaction occurs, one or more substances is changed into new substances

Change in temperatureChange in colorChange in odorFormation of a gas Formation of a solid precipitate Many chemical reactions are NOT reversible

physical change chemical change Classify each process as being a physical change only OR a process that also involves a chemical change (chemical reaction)

Boiling Decomposing Dissolving Baking

Three Phases

Solid Solid – definite volume and shape; particles packed in fixed positions. Liquid Liquid – definite volume but indefinite shape; particles close together but not in fixed positions Gas Gas – neither definite volume nor definite shape; particles are at great distances from one another Plasma – high temperature, ionized phase of matter as found on the sun. Phase Differences