Chapter 3 Flashcards
A theory where an acid is a substance that can donate (lose) a proton; a base is a substance that can accept (or remove) a proton
Brønsted-Lowry acid-base theory
A substance that can donate (or lose) a proton
Brønsted-Lowry acid
A substance that can accept (or remove) a proton
Brønsted-Lowry base
A chemical species that bears an electrical charge
Ion
The molecule or ion that forms when an acid loses its proton
Conjugate base
The molecule or ion that forms when a base accepts a proton
Conjugate acid
A substance that can transfer two protons
Diprotic acid
When an ionic compound dissolves in water
Solvated
Ions that play no part in the acid-base reaction
Spectator ions
A reaction involving ions as reactants, intermediates, or products; occur through the heterolysis of covalent bonds
Ionic reaction
Show the direction of electron flow in a reaction mechanism; point from source of electron or electron pair to the atom receiving the electron or electron pair. Double-barbed arrows indicate movement of a pair of electrons; single-barbed arrows indicate the movement of a single electron. They are never used to show the movement of atoms
Curved arrows
An acid is an electron pair acceptor, and a base is an electron pair donor
Lewis acid-base theory
Is an electron pair acceptor
Lewis acid
Is an electron pair donor
Lewis base
The cleavage of a covalent bond so that one fragment departs with both of the electrons of the covalent bond that joined them; normally produces positive and negative ions
Heterolysis
A chemical species in which a trivalent carbon atom bears a formal positive charge
Carbocation
A chemical species in which a carbon atom bears a formal negative charge
Carbanion
A Lewis acid, an electron-pair acceptor, an electron-seeking reagent
Electrophile
A Lewis base, an electron pair donor that seeks a positive center in a molecule
Nucleophile
The strength of an acid is related to its acidity content, Ka or to its pKa. The larger the value of the Ka or the smaller the value of its pKa, the stronger the acid
Acid strength
An equilibrium constant related to the strength of an acid
Acidity constant (Ka)
A constant that expresses the position of an equilibrium; it’s calculated by multiplying the molar concentrations of the products together and then dividing this number by the number obtained by multiplying together the molar concentrations of the reactants
Equilibrium constant (Keq)
The negative logarithm of the acidity content, Ka
pKa
The strength of a base is inversely related to the strength of its conjugate acid; weaker the conjugate acid, the stronger the base. If the conjugate acid has a large pKa, the base will be strong
Base strength
The molecule or ion that forms when an acid loses its proton
Conjugate base
An intrinsic electron-attracting or electron-releasing effect that results from a nearby dipole in the molecule and that is transmitted through space and through the bonds of a molecule
Inductive effect
The capacity to do work
Energy
Results from the motion of an object
Kinetic energy
Stored energy; it exists when attractive or repulsive forces exist between objects
Potential energy
The change in enthalpy after a system in its standard state has undergone a transformation to another system, also in its standard state
Enthalpy change (dH*)
A reaction that evolves heat; for this type of reaction, dH* is negative
Exothermic reaction
A reaction that absorbs heat; for this type of reaction, dH* is positive
Endothermic reaction
The change in free energy between two systems in their standard states
Free-energy change (dG*)
The change in entropy between two systems in their standard states; the more random a system is, the greater its entropy
Entropy change (dS*)
An effect by which a substituent exerts either an electron-releasing or electron-withdrawing effect through the pi system of the molecule
Resonance
The dispersal of electrons (or of electrical charge); always stabilizes a system
Delocalization effect
An effect on the rate of reaction (or on the equilibrium constant) caused by the replacement of a hydrogen atom by another atom or group; includes those effects caused by the size of the atom or group, called steric effects, and those effects caused by the ability of the group to release or withdraw electrons, called electronic effects
Substituent effect
A solvent whose molecules have a hydrogen atom attached to a strongly electronegative element such as oxygen or nitrogen
Protic solvent
The conjugate acid of an alcohol
Protonated alcohol/alkyloxonium ion
A chemical species with an oxygen atom that bears a formal positive charge
Oxonium ion
A step-by-step description of the events that are postulated to take place at the molecular level as reactants are converted to products
Reaction mechanisms
A reaction in which one group replaces another in a molecule
Substitution reaction
An effect that restricts the use of certain solvents with strong acids and bases. On principle, no acid stronger than the conjugate acid of a particular solvent can exist to an appreciable extent in that solvent, and no base stronger than the conjugate base of the solvent can exist to an appreciable extent in that solvent
Leveling effect of a solvent
Alkynes with a proton attached to a triply bonded carbon
Terminal alkynes
RO- ions
Alkoxide ions
