Chemical CompoundsChapter 10

State Standards:3.b; 3.c; 5.e; 7.c

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10-1: Ionic and Covalent Compounds

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Ionic Compounds

•Attraction between oppositely charged ions ▫(+ and -)▫Have ionic bonds

•Mostly metals and nonmetals▫Metal atoms become positively charged

when electrons are transferred to nonmetals

▫NaCl•

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(Na loses electrons, Cl gains electrons)

Ionic Compound Properties

•Brittleness▫Crystal lattice arrangement

•High melting point▫Because of strong bonds between ions

•Highly soluble (dissolve easily) in water

•Conducts electricity

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Covalent Compounds

•Atoms are bound by shared valence electrons

•Bonding of two nonmetals

•Molecules are made up of covalent compounds

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Covalent Compound Properties

•Most not very soluble (do not dissolve well in water)

•Low melting point▫Weaker bonds are easier to break

•Most do not conduct electricity because they do not form ions when dissolved in water

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Types of CompoundsIonic Covalent

Between positive and negative ions

Atoms share valence electrons

Metal and nonmetal Nonmetal and nonmetal

Brittle (crystal lattice structure)

Make molecules

Soluble Not very soluble

High melting point Low melting point

Conduct electricity Do not conduct electricity

Ex. Salt Ex. H2O

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10-2: Acids and Bases

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Acids•Have hydronium ions (H3O+)

▫H2O + H+ H3O+

•Uses▫Hydrochloric acid used in separating

metals from their ores, pool maintenance against algae, stomach digestion

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Acid Properties•Sour Taste

▫Corrosive – ability to destroy many things

•Change colors of indicators▫Litmus paper – changes to red

•React with metals to form hydrogen gas

•Conducts electric current▫When acids are dissolved in water, they

break apart and form ion

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Bases•Have hydroxide ions (OH-)

▫Hydroxide ion is an oxygen bonded to a hydrogen with a negative charge

•Uses▫Sodium hydroxide is used in soap, paper,

oven cleaners and drain decloggers

▫Ammonia – household cleaners and fertilizers

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Base Properties

•Bitter taste and slippery feel▫Corrosive▫Ex. Soap

•Change color of indicators▫Litmus paper – changes to blue

•Conduct electrical current▫Hydroxide ions have a negative charge

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Neutral Neutral Solution Solution (pH of 7)(pH of 7)

BasicBasic AcidicAcidic

pH ScalepH Scale

Acids vs. BasesAcids Bases

Hydronium Ions (H3O+)

Positive Charge

Hydroxide Ions (OH-)Negative Charge

Taste Sour Taste Bitter

Forms Ions in Water Feels Slippery

pH 0-7 pH 7-14

Turns Litmus Red Turns Litmus Blue

Ex. Battery Acid Ex. Cleaning Products

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10-3: Solutions of Acids and Bases

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Solutions of Acids and Bases•The concentration of an acid or base is not

the same as its strength

•Strong vs Weak acid▫In a strong acid, all of the acid molecules

break apart and form Hydrogen ions (H+) when dissolved in water. In a weak acid, only a few do.

•Strong vs Weak base▫In a strong base, all of the base molecules

break apart to form Hydroxide ions (OH-). In a weak base, only a few break apart.

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The pH Scale•Describes how acidic

or basic a solution is

•Measures the Hydronium ion (H3O+) concentration in a solution

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Salts•An ionic compound formed from positive

ion of a base and the negative ion of an acid

•When an acid neutralizes a base, salt and water are produced

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