General Chemistry 4: Compounds and stoichiometry

An [...] formula is the simplest whole-number ratio of atoms

empirical

The [...] formula shows the exact number of atoms of each element

molecular

• its is a multiple of the empirical formula

Two or more reactants forming one product

2H2 (g) + O2 (g) → 2H2O(g)

combination

Single reactant breaks down

2HgO(s) → 2Hg (l) + O2 (g)

decomposition

Involves a fuel, usually a hydrocarbon, and O2 (g)

Commonly forms CO2 and H2O

CH4 (g) + 2O2 (g) → CO2 (g) + H2O(g)

combustion

An atom/ion in a compound is replaced by

another atom/ion

Cu (s) + AgNO3 (aq) → Ag (s) + CuNO3 (aq)

single-displacement

Elements from two compounds swap places

CaCl2 (aq) + 2AgNO3 (aq) → Ca(NO3)2 (aq) + 2AgCl (s)

Double-displacement (metathesis)

A type of double-replacement reaction

Acid + base → salt + H2O

HCl (aq) + NaOH(aq) → NaCl (aq) + H2O(l)

Neutralization

For elements (usually metals) that can

form more than one positive ion, the

charge is indicated by a Roman numeral in

parentheses following the name of the

element

Fe2+ Iron(II)

Fe3+ Iron(III)

Cu+ Copper(I)

Cu2+ Copper(II)

Older method: –ous and –ic to the atoms

with lesser and greater charge,

respectively

Fe2+ Ferrous

Fe3+ Ferric

Cu+ Cuprous

Cu2+ Cupric

Monatomic anions drop the ending of the

name and add –ide

H- Hydride

F- Fluoride

O2- Oxide

S2- Sulfide

N3- Nitride

P3- Phosphide

Oxyanions = polyatomic anions that

contain oxygen.

MORE Oxygen = –ate

LESS Oxygen = –ite

NO3 - Nitrate

NO2 - Nitrite

SO42- Sulfate

SO3 2- Sulfite

In extended series of oxyanions, prefixes

are also used.

MORE Oxygen = Hyper- (per-)

LESS Oxygen = Hypo-

ClO- Hypochlorite

ClO2

- Chlorite

ClO3

- Chlorate

ClO4

- Perchlorate

Polyatomic anions that gain H+ to for

anions of lower charge add the word

Hydrogen or dihydrogen to the front.

HCO3

- Hydrogen carbonate or bicarbonate

HSO4

- Hydrogen sulfate or bisulfate

H2PO4

-

Dihydrogen phosphate

acid names

-ic: Have one MORE oxygen than -ous.

-ous: Has one FEWER oxygen than -ic.

equivalents and normality