Chapter 4 Notecards

the interaction between two axial groups that are on adjacent carbon atoms

hydrocarbons having one single (Sigma) bonds between carbon atoms said to be “saturated” because C–C single bonds cannot react to add hydrogen to the molecule

hydrocarbons having at least one double bond between carbon atoms said to be “unsaturated” because their C=C double bonds can react to add hydrogen to the molecule, yielding an alkane.

the designation given to a fragment of a molecule hypothetically derived from an alkane by removing a hydrogen atom this group’s names end in “-yl”.

hydrocarbons having at least one triple bond between carbon atoms these are said to be “unsaturated” because C≡C triple bonds can react to add to molecules of hydrogen to the molecule, yielding an alkane.

The CH2–CHCH2– group.

the increased potential energy of a molecule caused by deformation of a bond angle away from its lowest energy value.

the six bonds of a cyclohexane ring that are perpendicular to the general plane of the ring, and that alternate up and down around the ring.

a conformation of cyclohexane that resembles a boat and that has eclipsed bonds along its two sides. It is of higher energy than the chair conformation

the all-staggered confirmation of cyclohexane that has no angle strain or torsional strength and is, therefore, the lowest energy conformation

diastereomers that differ in their stereochemistry at adjacent atoms of a double bond or a different atoms of the ring. Cis groups are on the same side of a double bond or ring. Trans groups are on opposite sides of a double bond or ring.

rotations about the carbon-carbon single bonds of cyclohexane can produce different conformations which are intercountry double. The most important are the chair conformation, the boat conformation, and the twist conformation.

and an analysis of the energy changes that a molecule undergoes as its groups undergo rotation (sometimes only partial) about the single bonds that join them

stereoisomers differing in space only due to rotations about single (Sigma) bonds.

a particular temporary orientation of a molecule that results from rotations about it single bonds.

a particular staggered confirmation of a molecule.

compounds that have the same molecular formula but that differ in their connectivity (i.e., molecules that have the same molecular formula but have their atoms connected in different ways).

alkanes in which some or all of the carbon atoms are arranged in a ring. Saturated cycloalkanes have the general formulaCNH2N.

the angle between two atoms (or groups) bonded to Jason atoms, when viewed as a projection down the bond between the adjacent atoms.

a temporary orientation of groups around two atoms joined by a single bond such that the groups directly oppose each other.

six bonds of a cyclohexane ring that lie generally around the “equator” of the molecule

a system for naming compounds that uses two or more words to describe the compound. The final word corresponds to the functional group present; the preceding words, usually listed in alphabetical order, describe the remainder of the molecule.

a series of compounds in which each member differs from the next member by a constant unit.

a reaction which hydrogen adds to a double or triple bond. This is often accomplished to the use of a metal catalyst such as platinum, palladium, rhodium, or ruthenium.

electron Delocalization (via orbital overlap) from a failed bonding orbital to an adjacent unfilled orbital. This generally has a stabilizing effect

equals the number of pairs of hydrogen atoms that must be subtracted from the molecular formula of the corresponding alkane to give the molecular formula of the compound under consideration

a set of nomenclature rules overseen by the international Union of pure and applied chemistry that allows every compound to be assigned an unambiguous name.

a means of representing the spatial relationships of groups attached to two atoms of a molecule. In writing these, we imagine ourselves feeling the molecule from one end directly along the bond axes joining the two atoms. Bonds that are attached to the front atom are shown as radiating from the center of a circle; those attached to the rare atom are shown as radiating from the edge of the circle

an old name for an alkane

a graphical plot that measures the changes that occurs as molecules (or atoms) reacts (or interacts). Potential energy is plotted on the vertical axis, and the progress of the reaction on the horizontal axis.

the change in a cyclohexane ring (resulting from partial bond rotations) that converts one ring conformation to another. A chair-chair Ring flip converts any Equatorial substituents to an axial substituent and vice versa.

the increased potential energy of the cyclic form of a molecule (usually measured by sheets of combustion) when compared to its acyclic form.

a chemical formula that depicts the spatial relationships of groups in a molecule in a way similar to dash-wedge formulas.

a temporary orientation of groups around two atoms joined by a single bond such that the bond of the back atom exactly bisects the angles formed by the bonds of the front atom when shown in a Newman projection formula

compounds with the same molecular formula that differ only in the arrangement of their atoms in space. These have the same connectivity and, therefore, are not constitutional isomers. These are classified further as being either enantiomers or diastereomers

an effect on relative reaction rates cause when the spatial arrangement of atoms or groups at or near the reacting site hinders or retards reaction.

a system for naming compounds in which each atom or group, called a substituent, is cited as a prefix or suffix to a parent compound. In the IUPAC system only one group may be cited as a suffix. Locants (usually numbers) are used to tell where the group occurs.

the barrier to rotation of groups joined by a single bond caused by the potions between the aligned electron pairs in the eclipse form

the strain associated with an eclipsed conformation of a molecule; his cause by repulsion between the aligned electron pairs of the eclipsed bonds.

The CH2–CH– group.