General Chemistry: Bonding, Reactions, Stoichiometry, and Thermochemistry

Comprehensive vocabulary flashcards reviewing fundamental chemistry principles across chemical reactions, bonding, stoichiometry, and thermochemistry.

Balanced Chemical Equation

A chemical equation that represents chemical changes with equal numbers of each atom on both sides, including reactants, products, a reaction arrow, and stoichiometric coefficients.

Stoichiometric Coefficients

Numbers placed before each chemical species in a reaction to balance the equation, representing relative numbers of molecules, formula units, or moles, and ensuring the law of conservation of mass is followed.

Subscripts

Numbers written immediately after and slightly below an elemental symbol in a chemical formula that represent the number of each atom in that chemical species.

Synthesis (Combination) Reaction

A reaction classification in which two or more starting materials combine to form a single product, following the general pattern where two form one.

Decomposition Reaction

A chemical reaction in which a single reactant breaks down into two or more simpler products.

Single Displacement Reaction

A reaction in which one element replaces another element within a compound, such as a metal displacing another metal cation or an acid's hydrogen ion.

Double Displacement Reaction

A reaction in which two ionic compounds exchange ions with each other to produce two new compounds.

Precipitation Reaction

A double displacement reaction occurring between two soluble compounds that yields an insoluble solid product known as a precipitate.

Acid-Base Neutralization

A double displacement reaction between an acid and a base that produces water and a salt.

Cation

A positively charged ion formed when a neutral atom loses one or more electrons.

Anion

A negatively charged ion formed when a neutral atom gains one or more electrons.

Isoelectronic

Describes atoms or ions that possess the exact same number of electrons.

Polyatomic Ion

An ion composed of multiple atoms covalently bonded together that carries an overall net electrical charge; also referred to as a charged molecule.

Oxoanion

A polyatomic anion that contains oxygen bonded to a characteristic central element.

Coulomb's Law

A law stating that the electrostatic force of attraction between two charged particles ($F_e = k_e \frac{|q_1 q_2|}{r^2}$) is strongest when charges are large and the distance between them is small.

Crystal Lattice (Ionic Lattice)

A three-dimensional framework of alternating positive cations and negative anions extending in all directions.

Empirical Formula

A chemical formula that expresses the smallest whole-number ratio of ions or atoms present in a compound.

Formula Unit

The smallest neutral collection of ions necessary to form an ionic compound, such as $\text{NaCl}$ for sodium chloride.

Hydrate

An ionic compound that contains water molecules trapped within its crystal lattice in a specific stoichiometric ratio.

Covalent Bond

A chemical bond formed when two nonmetallic atoms share electrons.

Single Bond

A covalent linkage formed when two atoms share two electrons (one electron pair).

Molecular Formula

A chemical formula used for covalent compounds that provides the actual number of each atom in a molecule.

Binary Covalent Compound

A molecular compound composed of atoms from two different nonmetallic elements.

Ionization

The process that occurs when an ionic compound dissolves in water, whereby ions dissociate from one another and become solvated by water molecules.

Electrolyte Solution

An electrically conducting solution containing separated mobile cations and anions that carry an electric current.

Acid

A molecular compound typically containing a hydrogen atom that ionizes in aqueous solution to yield a hydrogen cation (proton, $H^+$) and a stable anion.

Binary Acid

An acid consisting of a hydrogen atom and a single nonmetal atom, typically a halogen, named using the prefix hydro- and suffix -ic.

Oxoacid

An acid consisting of one or more hydrogen atoms combined with an oxoanion.

Combustion Analysis

An elemental analysis method in which a sample is burned completely in excess oxygen, converting its carbon to $\text{CO}_2$ and its hydrogen to $\text{H}_2\text{O}$ to determine empirical formulas.

Mass Spectrometry

An analytical technique that ionizes molecules, accelerates them in an electric field, and deflects them in a magnetic field to determine molecular mass based on mass-to-charge deflection.

Thermodynamics

The study of the relationships between energy and temperature changes.

Thermochemistry

The branch of thermodynamics that specifically investigates energy changes associated with chemical changes.

Potential Energy

Stored energy that results from an object's position within a field of force.

Kinetic Energy

The energy possessed by an object due to its motion.

First Law of Thermodynamics

The law of conservation of energy stating that energy can neither be created nor destroyed; any energy lost by a system is gained by its surroundings and vice versa.

Exothermic Reaction

A process or reaction in which the system releases heat energy to its surroundings, characterized by a negative heat value ($-q$).

Endothermic Reaction

A process or reaction in which the system absorbs heat energy from its surroundings, characterized by a positive heat value ($+q$).

System

The specific chemical reaction or physical process currently being studied.

Surroundings

Everything in the universe outside of the thermodynamic system being studied.

Pressure-Volume Work

Expansion or compression work performed by or on a gas against an external pressure, given by the expression $w = -P\times\text{area}\times d = -P\times\text{change in volume}$.

Enthalpy ($H$)

A thermodynamic property defined as the total heat content of a system.

Specific Heat Capacity ($s$)

The quantity of heat required to raise the temperature of one gram of a substance by $1\,^\circ\text{C}$, calculated as $s = \frac{q}{m\Delta T}$.

Heat Capacity ($C$)

The amount of heat required to raise the temperature of an object by $1\,^\circ\text{C}$, regardless of the object's mass, calculated as $C = \frac{q}{\Delta T}$.

Calorimetry

The experimental technique used to measure heat flow during physical or chemical processes, conducted under conditions of constant pressure or constant volume.

Coffee Cup Calorimetry

A practical method of constant pressure calorimetry used to measure heat transferred in aqueous chemical reactions or heat exchange between materials.

Mole

The SI base unit for amount of substance that represents $6.02 \times 10^{23}$ representative units (atoms, molecules, or ions).

Avogadro's Number

The experimentally determined constant $6.02 \times 10^{23}$, indicating the number of particles found in one mole of a substance.

Molar Mass

The mass in grams of one mole ($6.02 \times 10^{23}$ particles) of an element or compound, expressed with the unit $g\,mol^{-1}$.

Stoichiometry

The branch of chemistry dealing with the quantitative relationships between amounts of reactants and products in chemical changes, derived from the Greek stoicheion (element) and metron (measure).

Limiting Reagent

The reactant that is completely consumed first in a reaction, thereby limiting and determining the maximum theoretical amount of product that can be generated.

Excess Reagent

A reactant present in an amount greater than required to react with the limiting reactant, leaving unreacted material remaining when the reaction ceases.

Molarity ($M$)

A unit of solution concentration defined as the moles of solute dissolved per unit volume of solution, expressed in $mol\,dm^{-3}$.

Gravimetric Analysis

An analytical quantitative technique used to determine the concentration of ions in solution from the mass of an insoluble precipitate formed in a chemical reaction.

Theoretical Yield

The maximum amount of product that can be calculated to form in a reaction based on complete conversion of the limiting reactant.

Actual Yield

The measured mass or amount of product physically obtained when a chemical reaction is carried out in the laboratory.

Percent Yield

The ratio of the actual yield to the theoretical yield expressed as a percentage: $\text{\% yield} = \frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100\%$.