Solutions for Chapter 9: Energy, Enthalpy, and Thermochemistry

The breaking of a bond, either homolytically or heterolytically. bond dissociation energy (Sect. 6.1): The energy required to achieve homolytic bond cleavage (generating radicals).

Valence electrons involved in forming a covalent bond (i.e., shared electrons).

A CRO bond. carboxylic acid derivative (Sect. 21.6): A compound that is similar in structure to a carboxylic acid (RCOOH) but the OH group of the carboxylic acid has been replaced with a different group, Z, where Z is a heteroatom such as Cl, O, N, etc. Nitriles (R!C#N) are also considered to be carboxylic acid derivatives because they have the same oxidation state as carboxylic acids.

A [3,3] sigmatropic rearrangement that is observed for allylic vinylic ethers.

A shift of an equilibrium induced by an ion common to the equilibrium. For example, added Na2SO4 decreases the solubility of the slightly soluble salt BaSO4, or added NaF decreases the percent ionization of HF. (Section 17.1)

Compounds containing only covalent bonds. (9.4)

An effect that causes different regions of space to be characterized by different magnetic field strengths.

Refers to the steric strain arising from interaction between an axial substituent and an axial hydrogen (or other group) on the same side of a chair conformation of a cyclohexane ring

A compound containing a hydroxyl group (OH) and an alkoxy group (OR) connected to the same carbon atom.

The equilibrium established between substances in two or more different phases, for example, between a gas and a solid or between a solid and a liquid. (Section 15.4)

A substance formed in one elementary step of a multistep mechanism and consumed in another; it is neither a reactant nor an ultimate product of the overall reaction. (Section 14.6)

A group capable ofseparating from a compound.

A group that is used during synthesis to protect a functional group from the reaction conditions.

An acid that is a proton donor in an acidbase reaction.

The step in a multistep reaction sequence that crosses the highest energy barrier.

Compounds containing silicon and oxygen, structurally based on SiO4 tetrahedra. (Section 22.10)

A plant or animal lipid having the characteristic tetracyclic ring structure of the steroid nucleus, namely three sixmembered rings and one fi ve-membered ring.

A polymer with alternating R and S confi gurations at the chiral centers along its chain, as, for example, syndiotactic polypropylene

A compound that contains two SR groups, both of which are connected to the same carbon atom.

A term used to describe two identical groups attached to adjacent carbon atoms.