General Chemistry: Nomenclature, Reactions, and Stoichiometry

Comprehensive vocabulary review of chemical nomenclature, reaction classification, balanced molecular and ionic equations, stoichiometric conversions, and empirical formulas.

Law of Definite Proportions

The chemical principle stating that elements in a pure compound always combine in fixed mass ratios.

Formula Mass

The mass calculated by adding the atomic masses of all atoms present in a compound's formula unit.

Ionic Nomenclature

The naming system for compounds composed of a metal and a nonmetal or polyatomic ion, structured as cation name plus anion name (with an -ide suffix unless polyatomic), including Roman numerals for metals with variable charge.

Covalent / Molecular Nomenclature

The naming system for compounds composed of two nonmetals that uses Greek prefixes (such as mono-, di-, tri-, tetra-) to designate quantity, omitting the prefix mono- on the first element.

Binary Acids

Acids containing no oxygen that are named using the prefix hydro-, the base name of the nonmetal, and the suffix -ic acid (e.g., $HCl(aq)$ is hydrochloric acid).

Oxyacids

Oxygen-containing acids named based on the polyatomic anion: anions ending in -ate become -ic acid, while anions ending in -ite become -ous acid.

The 3-Step Mole Conversion Path

The stoichiometric sequence used to convert between quantities: $\text{Grams} \longleftrightarrow \text{Moles} \longleftrightarrow \text{Particles / Molecules / Formula Units}$.

Empirical Formula Procedure

The four-step process to find simplest ratios: 1. Convert percentages to grams assuming a $100\,g$ sample; 2. Convert grams to moles using molar mass; 3. Divide all mole values by the smallest mole value; 4. Multiply by an integer factor if necessary to achieve whole-number subscripts.

Molecular Formula Procedure

The method of determining a true molecular formula by solving for the multiplier $n = \frac{\text{Molar Mass of Compound}}{\text{Empirical Formula Mass}}$ and multiplying each empirical subscript by $n$.

Synthesis / Combination Reaction

A reaction where two or more reactants combine to form a single compound, following the pattern $A + B \rightarrow AB$.

Decomposition Reaction

A reaction where a single compound breaks down into two or more elements or simpler compounds, following the pattern $AB \rightarrow A + B$.

Single Displacement Reaction

A reaction where one element displaces another element from a compound, following the pattern $A + BC \rightarrow AC + B$.

Double Displacement / Metathesis Reaction

A reaction in which two compounds exchange ions or partner elements to form two new compounds, represented as $AB + CD \rightarrow AD + CB$.

Precipitation Reaction

A type of double displacement reaction where two aqueous solutions combine to form an insoluble solid product.

Acid-Base Neutralization Reaction

A reaction type (classified as double displacement) occurring when an acid reacts with a base to form water and a salt: $\text{Acid} + \text{Base} \rightarrow \text{Water} + \text{Salt}$.

Combustion Reaction

A reaction in which a compound reacts rapidly with oxygen gas to yield carbon dioxide and water: $\text{Compound} + O_2 \rightarrow CO_2 + H_2O$.

Redox Reaction

A chemical reaction involving electron transfer, defined by oxidation (the loss of electrons, $e^-$) and reduction (the gain of electrons, $e^-$), summarized by the mnemonic OIL RIG.

Molecular Equation

A representation of a chemical reaction displaying full chemical formulas of all reactants and products accompanied by phase labels.

Complete Ionic Equation

An equation showing all strong, soluble aqueous electrolytes separated into their constituent ions, while retaining solids $(s)$, liquids $(l)$, and gases $(g)$ intact.

Net Ionic Equation

An equation derived by removing all spectator ions from a complete ionic equation, leaving only the species directly involved in the chemical transformation.

Spectator Ions

Ions that remain unchanged in the aqueous phase on both the reactant and product sides of a chemical reaction and are cancelled out to yield the net ionic equation.

$$SO_3$$

Sulfur trioxide.

$$N_2F_2$$

Dinitrogen difluoride.

$$Fe_3(PO_4)_2$$

Iron(II) phosphate.

$$HF(aq)$$

Hydrofluoric acid.

$$Na_2O$$

Sodium oxide.

$$Mn(ClO)_4$$

Manganese(IV) hypochlorite.

Nickel(I) bicarbonate

An ionic compound with the chemical formula $NiHCO_3$.

Chlorine trioxide

A molecular compound with the chemical formula $ClO_3$.

Zinc chloride

An ionic compound with the chemical formula $ZnCl_2$.

Barium hydroxide

A compound with the chemical formula $Ba(OH)_2$.

Nitrous acid

An aqueous oxyacid with the chemical formula $HNO_2(aq)$.

Copper(II) nitrate

An ionic salt with the chemical formula $Cu(NO_3)_2$.

Formula Units and Nitrogen Content of $Cu(NO_2)_2$

In $0.92\,mol$ of $Cu(NO_2)_2$, there are $0.92\,mol \times 6.022 \times 10^{23}\,\frac{\text{units}}{mol} = 5.5 \times 10^{23}\text{ formula units}$, containing $1.1 \times 10^{24}\text{ atoms of N}$ ($5.54 \times 10^{23}\text{ units} \times 2$).

Strontium Mass Fraction in $Sr_3(PO_4)_2$

The mass percentage calculated as $\frac{3(87.62)}{452.8} = 58.05\%$, corresponding to $0.592\,g$ ($592\,mg$) of $Sr$ in a $1.02\,g$ sample with a molar mass of $452.8\,g/mol$.

Ritalin (Chemical Formula Analysis)

A substance with elemental composition $72.07\%\,C$, $13.72\%\,O$, $8.21\%\,H$, and $6.00\%\,N$; resulting in an empirical mass of $233.31\,g/mol$ and matching empirical and molecular formulas of $C_{14}H_{19}NO_2$.

Sodium Carbonate and Calcium Nitrate Reaction Equations

A precipitation/double displacement process with molecular equation $Na_2CO_3(aq) + Ca(NO_3)_2(aq) \rightarrow CaCO_3(s) + 2NaNO_3(aq)$, complete ionic equation $2Na^+(aq) + CO_3^{2-}(aq) + Ca^{2+}(aq) + 2NO_3^-(aq) \rightarrow CaCO_3(s) + 2Na^+(aq) + 2NO_3^-(aq)$, and net ionic equation $Ca^{2+}(aq) + CO_3^{2-}(aq) \rightarrow CaCO_3(s)$.