MATTER AND CHANGE Chemistry The study of matter

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MATTER AND CHANGE

MATTER AND CHANGE

Chemistry: The study of matter and the changes it undergoes.

Chemistry: The study of matter and the changes it undergoes.

Matter Anything that has mass and takes up space

Matter Anything that has mass and takes up space

Alchemical view of matter

Alchemical view of matter

Matter • Atoms are the building blocks of matter

Matter • Atoms are the building blocks of matter

Matter “Space-filling” models of molecules

Matter “Space-filling” models of molecules

Matter Oxygen Hydrogen Each element is made of the same kind of atom

Matter Oxygen Hydrogen Each element is made of the same kind of atom

Each element is made of the same kind of atom with unique set of

Each element is made of the same kind of atom with unique set of properties

Carbon Uncut diamond Graphite Uncut diamond with impurities

Carbon Uncut diamond Graphite Uncut diamond with impurities

STATES OF MATTER: Solid, Liquid, Gas (a) Particles in solid (b) Particles in liquid

STATES OF MATTER: Solid, Liquid, Gas (a) Particles in solid (b) Particles in liquid (c) Particles in gas

STATES OF MATTER • SOLIDS – Definite shape and volume – Particles of a

STATES OF MATTER • SOLIDS – Definite shape and volume – Particles of a solid packed tightly together – NOT easily compressed

SOLIDS

SOLIDS

STATES OF MATTER • LIQUIDS – Particles in close contact but arrangement is not

STATES OF MATTER • LIQUIDS – Particles in close contact but arrangement is not orderly or fixed – Definite volume – NOT easily compressed

In a liquid • molecules are in constant motion Liquid • there appreciable intermolecular

In a liquid • molecules are in constant motion Liquid • there appreciable intermolecular forces • molecules are close together • Liquids are almost incompressible • Liquids do not fill the container H 2 O(l) Water Zumdahl, De. Coste, World of Chemistry 2002, page 31

STATES OF MATTER • GAS – Particles NOT in close contact and are constantly

STATES OF MATTER • GAS – Particles NOT in close contact and are constantly moving – No definite volume

Some Properties of Solids, Liquids, and Gases Property Solid Liquid Gas Shape Has definite

Some Properties of Solids, Liquids, and Gases Property Solid Liquid Gas Shape Has definite shape Takes the shape of the container Takes the shape of its container Volume Has a definite volume Fills the volume of the container Arrangement of Particles Fixed, very close Random, far apart Interactions between particles Very strong Strong Essentially none

How to describe matter… • Extensive properties – Depends on the AMOUNT of matter

How to describe matter… • Extensive properties – Depends on the AMOUNT of matter in a sample • Mass • Volume • Intensive properties – Depends on the TYPE of matter in a sample • Color • Temperature • Density

SUBSTANCE • Matter that has a uniform and definite composition • Every sample of

SUBSTANCE • Matter that has a uniform and definite composition • Every sample of a given substance has identical intensive properties because every sample has the same composition • Elements CANNOT be broken down into simpler components • Compounds CAN be broken down into elements

Examples of pure substances GOLD ALUMINUM

Examples of pure substances GOLD ALUMINUM

Compounds • Made of two or more different kinds of elements chemically combined in

Compounds • Made of two or more different kinds of elements chemically combined in a fixed proportion. – for example: • Common table salt is a one to one combination of sodium atoms (Na) and chlorine atoms (Cl) = Na. Cl

What do we mean by “chemically combined”? • Elements in compounds are joined by

What do we mean by “chemically combined”? • Elements in compounds are joined by chemical bonds. – Examples of chemical bonds: • Ionic bond (electrostatic attraction that binds oppositely charged ions) – Usually composed of metal and nonmetal atoms • Covalent bond (bond that forms by the sharing of electrons between atoms) – Usually composed of carbon atoms bonded to elements such as hydrogen, oxygen, nitrogen and sulfur

Properties of Compounds • Compounds can be broken down into simpler substances by chemical

Properties of Compounds • Compounds can be broken down into simpler substances by chemical means but elements cannot. • Compounds and the elements from which they are formed have different properties

Examples of Compounds • Sugar (sucrose) – Composed of carbon, hydrogen and oxygen •

Examples of Compounds • Sugar (sucrose) – Composed of carbon, hydrogen and oxygen • Sugar a sweet-tasting white solid but carbon is a black, tasteless solid; Hydrogen and oxygen are odorless gasses Sugar Carbon + Water http: //www. youtube. com/watch? v=A_jt. Op. AYG 70

Sugar (sucrose)

Sugar (sucrose)

Sugar (sucrose)

Sugar (sucrose)

Properties of Matter • Physical properties: – Can be observed without changing a substance

Properties of Matter • Physical properties: – Can be observed without changing a substance into another substance • Boiling point, density, mass, volume, magnetic

Properties of Matter • Physical changes – Changes in matter that do NOT change

Properties of Matter • Physical changes – Changes in matter that do NOT change the composition of a substance • Changes of state (liquid to a gas), temperature (melting point), volume, crush, grind • Chemical changes – Changes that result in a new substance • Combustion, oxidation, decomposition

Mixtures • Physical blend of two or more components • Heterogeneous = composition is

Mixtures • Physical blend of two or more components • Heterogeneous = composition is variable throughout the sample • Homogeneous = composition is uniform throughout the sample

Classification of Matter

Classification of Matter