Chemistry Regents Review Flashcards

This set of vocabulary flashcards summarizes the core chemical principles, definitions, and theories from the lecture notes, including Equilibrium, Atomic Structure, Nuclear Chemistry, and Electrochemistry.

Collision Theory

The requirement that particles must collide with enough energy and proper arrangement for a reaction to occur.

Exothermic Reaction

A chemical reaction that releases energy, where heat is treated as a product and $\Delta H$ is negative.

Endothermic Reaction

A chemical reaction that absorbs energy, where heat is treated as a reactant and $\Delta H$ is positive.

Entropy

A measure of the randomness or disorder within a system.

Le Chatelier's Principle

The observation that if a stress is applied to a system at equilibrium, the system will shift its position to reduce that stress.

Radioactivity

The spontaneous emission of radiation from an unstable atomic nucleus.

Transmutation

A nuclear reaction that occurs when an atomic nucleus is changed into the nucleus of a different element.

Fission

The splitting of a heavy nucleus into lighter nuclei, typically initiated by bombarding the nucleus with a neutron.

Fusion

A nuclear reaction where light nuclei combine into one larger, heavier nucleus.

Gold Foil Experiment

Rutherford's experiment that concluded atoms are mostly empty space with a dense, positively charged core called the nucleus.

Wave-Mechanical Model

The modern atomic theory stating that the exact position of an electron cannot be known; electrons are located in regions called orbitals.

Orbital

A region of most probable location for an electron outside the nucleus in the Wave-Mechanical Model.

Isotope

Atoms of the same element that possess the same number of protons but have a different number of neutrons, resulting in different masses.

Valence Electrons

The electrons located in the outermost shell of an atom.

Electronegativity

A measure of the strength of attraction an atom has for electrons in a chemical bond.

Ionization Energy

The amount of energy required to remove the most loosely held electron from an atom in the gaseous state.

Diatomic Elements

Elements that are never found as single neutral atoms in nature: $I_2$, $Br_2$, $Cl_2$, $F_2$, $O_2$, $N_2$, and $H_2$.

Empirical Formula

A chemical formula showing the simplest whole-number ratio of atoms in a compound.

Molar Mass

Also known as gram formula mass, it is the sum of the atomic masses of all atoms in one mole of a substance.

Ionic Bond

A chemical bond formed between a metal and a nonmetal via the transfer of electrons resulting in attraction between oppositely charged ions.

Covalent Bond

A chemical bond formed between two or more nonmetals by the sharing of electrons.

Hydrogen Bond

A strong intermolecular force of attraction occurring between molecules containing hydrogen and atoms of small radius and high electronegativity, such as $F$, $O$, or $N$.

Molarity

A measure of solution concentration, defined as the ratio of moles of solute per liter of solution: $\text{Molarity} = \frac{\text{moles of solute}}{\text{Liters of solution}}$.

Electrolyte

A substance, such as an acid, base, or salt, that breaks into ions and conducts electricity when dissolved in water or melted.

Arrhenius Acid

A compound that yields hydrogen ions ($H^+$) as the only positive ions in an aqueous solution.

Arrhenius Base

A compound that yields hydroxide ions ($OH^-$) as the only negative ions in an aqueous solution.

Catalyst

A substance that speeds up a chemical reaction by providing an alternate reaction pathway with a lower activation energy.

Oxidation

A chemical process where a species loses electrons and its oxidation number increases ($LEO$).

Reduction

A chemical process where a species gains electrons and its oxidation number decreases ($GER$).

Voltaic Cell

An electrochemical cell that produces electrical energy from a spontaneous chemical redox reaction.

Electrolytic Cell

An electrochemical cell that utilizes an external power source to force a non-spontaneous redox reaction to occur.

Anode

The electrode in an electrochemical cell where oxidation occurs ($AN\,OX$).

Cathode

The electrode in an electrochemical cell where reduction occurs ($RED\,CAT$).

Salt Bridge

A component of a voltaic cell that permits the migration of ions between half-cells to maintain electrical neutrality.