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Chapter 3: Molecules, Compounds and Chemical Equations: Nomenclature, sections 3.1-3.7, 3.12

Homework:

Read Chapter 3: Work out sample/practice exercises.

Memorize the polyatomic ions, diatomic elements, prefixes for binary molecules, the

first ten alkanes, and the Nomenclature rules of naming.

Check for the MasteringChemistry.com assignment and complete before due date

Pure Substances and Mixtures:

Pure substances have one invariable composition (elements and compounds)

Mixtures have a variable composition. Homogeneous mixtures (solutions) are

those in which the mixing is uniform throughout the mixture (coffee, salt water,

air) while Heterogeneous mixtures are those in which the mixture is not

uniform, they vary in texture and have regions of different composition (soil,

pencil). This section will give the rules on how to name simple pure substances.

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Chemical Bonds: Covalent bonds share electrons and are found in molecules made up when two

or more nonmetals combine.

Ionic bonds transfer electrons and are found in compounds made up from

combining cations (metals, positively charged) with anions (nonmetals,

negatively charged). The cation is always before the anion in the formula. The

net charge of the compound is zero.

Propane, C3H8 Sodium Chloride, NaCl

Acids and Bases:

Acids are substances that increase H+1 ions in water. The cation is H+1.

Bases are substances that increase OH-1 ions in water. The anion is often OH-1.

Structural Formula will show the specific connections between atoms within a molecule

and gives more information than a chemical formula alone.

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Empirical Formula is the simplest whole number ratio between atoms.

Nomenclature: Elements

Most elements are written in an atomic form and given the element name: Cu-

copper, He-Helium, Zn-zinc

Seven elements are diatomic and are called by their element name:

H2-hydrogen, N2, O2, F2, Cl2, Br2, I2

A couple are polyatomic:

P4 is phosphorus, S8 is sulfur

Some elements form more than one molecule/structure (allotropes)

O2 is oxygen, O3 is ozone; C(graphite), C(diamond), C60

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Common names

Some molecules have been around so long they go by a common name:

H2O-water, NH3-ammonia, CH4-methane, SiH4-silane

Binary molecules

CO2, P2O4, CCl4

Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca

Prefix (not mono) element name prefix root of element plus ide

Carbon dioxide

Drop the a before an o, pentoxide, not pentaoxide.

Organic molecules

Alkanes (CnH2n+2)

Methane CH4, ethane C2H6, propane C3H8, butane C4H10, pentane

C5H12, hexane C6H14, heptane C7H16, octane C8H18, nonane C9H20,

decane C10H22

Functionalized hydrocarbons: alcohol, ether, aldehyde, ketone, carboxylic

acid, ester amine to name a few.

Alcohols (replace one H in alkane with an OH)

Methanol, CH3OH; propanol, C3H7OH

Carboxylic acids ( X–COOH, where the C is both double bonded to one O

and single bonded to an OH). These compounds generally use their

common name

HCOOH; formic acid and also known as methanoic acid

CH3COOH or HC2H3O2; acetic acid, also known as ethanoic acid

Ionic compounds (write cation name then anion name)

Cations with known oxidation state of metal

Group 1A (+1), 2A (+2) , Al and Ga (+3), Zn and Cd (+2), Ag (+1)

Name of ion is identical to the name of the atom for cations

Variable oxidation state of metal

Transition metals and metals below the nonmetal on the right have a

variable oxidation state that must be indicated by Roman Numerals in

parenthesis (this method is what I expect you to learn.

Fe+3, iron (III); Fe+2, iron (II); Cu+1, copper (I); Sn+4, tin (IV)

An alternative method differentiates from the higher oxidation number

and lower oxidation number using the old form of the name and ic or

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ous as an ending respectively. (you should be aware of this method, but

it will not be on a test)

Fe+3, ferric Fe+2, ferrous; Cu+2, cupric; Cu+1, cuprous; Sn+4, stannic;

Sn+2, stannous.

Elemental Anions

Group VA (-3); VIA (-2), VIIA (-1)

Name of the element root followed by ide.

N-3, nitride; S-2, sulfide, Br-1, bromide

Polyatomic cations and anions

Memorize the polyatomic ions and be able to evaluate ion names,

formulas, and charges following some basic rules.

Acids

Binary acids-H+ cation and an anion that ends with ide.

Hydro root of element ic acid. H2S, hydrosulfuric acid

Ternary oxyacids-H+1 cation with and anion ending in ate or ite

ate changes to ic acid, do not use hydro

H2SO4 becomes sulfuric acid

ite changes to ous acid, do not use hydro

H2SO3 becomes sulfurous acid

Hydrates

Ionic compounds can be chemically attached to a small number of water

molecules in a solid form. CuSO4.5H2O, copper (II) sulfate pentahydrate

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Nomenclature Practice:

Fill in the table with formulas and names of the ionic compounds.

Cl* CO3

-2 AsO4-3 OH-1

H+1

Zn*

Fe+3

Sn+4

NH4+1

Al*

*predict the known oxidation number

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Nomenclature Practice:

Names Formulas

Aluminum sulfide

Sodium carbonate

Tetraphosphorus decoxide

Nickel (II) chloride

Butane

Ammonium phosphate

Ethanol

Hydrosulfuric acid

Sulfuric acid

Sulfurous acid

Cobalt (II) chloride hexahydrate

H3PO4

H2C2O4 (aq)

H2O2

HBr (g)

HBr (aq)

MgSO4.7H2O

C8H18

PCl5

CuCr2O7

(NH4)2HPO4

KMnO4

__________________________ Fe(NO2)3