ACS General Chemistry Review - Vocabulary Flashcards

This set covers foundational and advanced general chemistry vocabulary including stoichiometry, thermodynamics, kinetics, equilibrium, and nuclear chemistry based on the ACS Official Guide.

Standard Temperature and Pressure (STP)

Defined as $0\,°C$ and $1\,\text{bar}$ of pressure; conditions under which most gases behave ideally.

Lattice Energy

The amount of energy required to completely separate $1\,\text{mole}$ of a solid ionic compound into its gaseous ions.

Isotopes

Atoms with the same number of protons (atomic number $Z$) but differing numbers of neutrons, resulting in different mass numbers ($A$).

Effective Nuclear Charge ($Z_{\text{eff}}$).

The net positive charge experienced by valence electrons, calculated as the actual nuclear charge minus the shielding constant ($Z_{\text{eff}} = Z_{\text{nuclear}} - \text{shielding}$).

Paramagnetic

A species that contains one or more unpaired electrons and is attracted to a magnetic field.

Enthalpy of Formation ($\Delta H_f^\circ$)

The enthalpy change for a reaction that produces $1\,\text{mole}$ of a substance from its constituent elements in their standard states.

Weak Electrolyte

A substance that only partially ionizes or dissociates when dissolved in water, resulting in poor electrical conductivity.

Molality ($m$)

A concentration unit defined as the moles of solute divided by the mass of the solvent in kilograms ($\text{mol solute} \, / \, \text{kg solvent}$).

Colligative Properties

Physical properties of solutions (like freezing point depression and osmotic pressure) that depend only on the number of solute particles, not their identity.

Activation Energy ($E_a$)

The minimum amount of energy required for a chemical reaction to occur upon collision of reactants.

Reaction Quotient ($Q$)

A ratio of the concentrations of products to reactants at any point in a reaction, calculated using the same expression as the equilibrium constant ($K$).

Brønsted-Lowry Acid

A substance that acts as a proton ($H^+$) donor in a chemical reaction.

Lewis Base

A substance that can donate a nonbonding (lone) pair of electrons to form a covalent bond.

Entropy ($S$)

A thermodynamic state function representing the distribution of energy or randomness in a system; values increase with temperature (S_{solid} < S_{liquid} < S_{gas}).

Gibbs Free Energy ($G$)

A thermodynamic property used to predict spontaneity ($\Delta G = \Delta H - T\Delta S$); a negative $\Delta G$ indicates a spontaneous process.

Anode

The electrode in an electrochemical cell where oxidation (loss of electrons) occurs.

Faraday Constant ($F$)

A physical constant representing the charge of one mole of electrons, approximately equal to $96485\,C\,mol^{-1}$.

Alpha ($\alpha$) Decay

A nuclear reaction where an atom emits a helium nucleus ($_2^4He$), decreasing the mass number by 4 and the atomic number by 2.

Beta ($\beta$) Decay

A nuclear reaction where a neutron transforms into a proton and emits an electron ($_{-1}^0e$), increasing the atomic number by 1 without changing the mass number.

Hybridization

The mixing of atomic orbitals ($s, p, d$) to form new hybrid orbitals ($sp, sp^2, sp^3$) for bonding in valence bond theory.