Chapter 3

Solid, Liquid and Gas

Classification of Matter

Separation Techniques

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

Gas, Liquid, and Solid

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 441

Gas Liquid Solid

Some Properties of Solids, Liquids, and Gases

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 (compressible)

Interactions between Very strong Strong Essentially noneparticles

MATTER

Can it be physically separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture Compound Element

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition uniform?

noyes

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Pure SubstancesElement– composed of identical atoms– EX: copper wire, aluminum foil

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Pure Substances

Compound

– composed of 2 or more elements in a fixed ratio

– properties differ from those of individual elements

– EX: table salt (NaCl)

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Mixtures

Variable combination of 2 or more pure substances.

Heterogeneous Homogeneous

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Pure Substances

Law of Definite CompositionLaw of Definite Composition

– A given compound always contains the same, fixed ratio of elements.

Law of Multiple ProportionsLaw of Multiple Proportions

– Elements can combine in different ratios to form different compounds.

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Pure Substances

For example…

Two different compounds, each has a definite composition.

Carbon, C Oxygen, O Carbon monoxide, CO

Carbon, C Oxygen, O Oxygen, O Carbon dioxide, CO2

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Mixtures

Solution– homogeneous– very small particles

Tyndall Effect

– particles don’t settle– EX: rubbing alcohol

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Air is a Solution

AirAir

NitrogenNitrogen

OxygenOxygenHeliumHelium

Watervapor

Watervapor

NeonNeon

Carbondioxide

Carbondioxide ArgonArgon

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 34

Solid Brass

An alloy is a mixture of metals.

• Brass = Copper + Zinc• Solid brass

• homogeneous mixture

Copper

Zinc

Classification of Matter

MATTER(gas. Liquid,

solid, plasma)

PURESUBSTANCES MIXTURES

HETEROGENEOUSMIXTURE

HOMOGENEOUSMIXTURESELEMENTSCOMPOUNDS

Separated by

physical means into

Separated by

chemical means into

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

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

Classify the following as element, compound, solution, or heterogeneous

mixture

• Copper

• H2O

• Salt in water

• Air

• Sand in water

• Sulfur

Separation of MixturesFiltration

Distillation

Crystallization

Chromatography

Filtration

• Filter paper placed in a funnel is used to separate a solid from a liquid. The solid will stay on the filter paper and the liquid flows through the paper to a collection beaker below.

The solution is boiled and steam is driven off.

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 39

Separation of a sand-saltwater mixture.

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 40

Crystallization

• Formation of a pure solid from a solution. An example of this is rock candy.

Paper Chromatography

• Separates the parts of a mixture as it travels across the surface of another material.

Conservation of Mass

• Mass cannot be created or destroyed.

Mass of Reactants=Mass of Products

(reactants) (products)

Magnesium + Oxygen Magnesium Oxide

10.0 g + ?? 16.6 g

How much oxygen reacts with the magnesium to form the magnesium oxide?

Pure Substances

Law of Definite CompositionLaw of Definite Composition

– A given compound always contains the same, fixed ratio of elements.

Law of Multiple ProportionsLaw of Multiple Proportions

– Elements can combine in different ratios to form different compounds.

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Pure Substances

For example…

Two different compounds, each has a definite composition.

Carbon, C Oxygen, O Carbon monoxide, CO

Carbon, C Oxygen, O Oxygen, O Carbon dioxide, CO2

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Sucrose

• The formula is C6H12O6

• Every sample of sucrose contains 42.1% carbon, 6.48% hydrogen and 51.4% oxygen.