Physical and Chemical PropertiesExamples of Physical Properties

Boiling point Color Slipperiness Electrical conductivity

Melting point Taste Odor Dissolves in water

Shininess (luster) Softness Ductility Viscosity (resistance to flow)

Volatility Hardness Malleability Density (mass / volume ratio)

Examples of Chemical Properties

Burns in air Reacts with certain acids Decomposes when heated

Explodes Reacts with certain metals Reacts with certain nonmetals

Tarnishes Reacts with water Is toxic

Ralph A. Burns, Fundamentals of Chemistry 1999, page 23Chemical properties can ONLY be observed during a chemical reaction!

Evidence a Chemical Change

Indications of a Chemical Reaction

– Evolution of heat, light, and/or sound

– Production of a gas

– Formation of a precipitate

– Color change

Formation of a solid: AgCl

AgNO3(aq) + KCl(aq) KNO3 (aq) + AgCl(s)

The Zeppelin LZ 129 Hindenburg catching fire on May 6, 1937 at Lakehurst Naval Air Station in New Jersey.

Matter: Solids, Liquids, and Gases (also Plasma)Property Solid Liquid Gas

Shape Has definite shape Takes the shape of Takes the shape the container of its container

Volume Has a definite volume Has a definite volume Fills the volume of the container

Arrangement of Fixed, very close Random, close Random, far apartParticles

Interactions between Very strong Strong Essentially noneparticles

Conservation of Mass

Reactants yield Products

Burning Magnesium Metal in an Open Container

Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 77

Burning Magnesium Metal in a Closed Container

Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 77

Classification of Matter

MATTER(gas. Liquid,

solid, plasma)

PURESUBSTANCES MIXTURES

HETEROGENEOUSMIXTURE

HOMOGENEOUSMIXTURES

ELEMENTSCOMPOUNDS

Separated by

physical means into

Separated by

chemical means into

Kotz & Treichel, Chemistry & Chemical Reactivity, 3rd Edition , 1996, page 31

Pure Substances

Element– composed of identical atoms– homogenous– EX: copper wire, aluminum foil

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Pure Substances

Compound– composed of 2 or more elements in a

fixed ratio by mass

– properties differ from those of individual elements

– homogenous

– EX: table salt (NaCl)

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Mixtures

Variable combination of 2 or more pure substances.

Heterogeneous (uneven mix)

Homogeneous (even mix)

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Elements, Compounds, and Mixtures

(a)an element(hydrogen)

(b)a compound(water)

(c)a mixture(hydrogen and oxygen)

(d)a mixture(hydrogenand oxygen)

Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 68

hydrogenatoms hydrogen

atoms

oxygen atoms

Solid, Liquid, Gas

(a) Particles in solid (b) Particles in liquid (c) Particles in gas

Solid

H2O(s) Ice

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 31

Liquid

H2O(l) Water

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 31

In a liquid• molecules are in constant motion• there are appreciable intermolecular forces• molecules are close together• Liquids are almost incompressible• Liquids do not fill the container

Gas

H2O(g) Steam

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 31

Liquids

The two key properties we need to describe areEVAPORATION and its opposite CONDENSATION

add energy and break intermolecular bonds

EVAPORATION

release energy and form intermolecular bonds

CONDENSATION