Chem&219 Unit 2
Acyclic compounds - Correct Answer Molecules whose skeletons do not contain any rings. The carbon chains of
acyclic molecules can be linear or branched and may consist of alkanes, alkenes, or alkynes.
Addition of Acids to Alkenes/Alkynes - Correct Answer When acids (HCl, HBr, HI, HF, and H-OSO3H [sulfuric acid])
are added to alkenes or to alkynes.
Acids have the general structure of H-A, where H is the acidic proton (the proton typically donated or released when
the molecule acts as an acid) and "A" represents the rest of the molecule to which the acidic H is attached. When an
acid reacts with an alkene, the H is added to one carbon, and the "A" (the remainder of the acid) becomes attached
to the other carbon.
addition reaction - Correct Answer An addition reaction adds atoms or groups of atoms to each carbon of the multiple
bond (they are added across the double bond). As they bond to each carbon it causes the double bond between the
carbons to become a single bond.
The most common reaction for alkenes and alkynes.
Addition reactions can also be viewed as combination reactions since two different molecules (alkene substrate and
another molecule) join to form a single new compound.
alcohol - Correct Answer The product of the hydration of an alkene is an alcohol - an organic molecule containing the
hydroxyl (-OH) functional group.
aliphatic hydrocarbons - Correct Answer The first major class of hydrocarbon molecules, made up of by alkanes,
alkenes, and alkynes
Alkanes - Correct Answer A type of hydrocarbon that are considered a saturated hydrocarbons because the skeleton
is composed of only C-C single bonds.
Alkenes (also called olefins) - Correct Answer Hydrocarbons with one or more C=C (double) bonds in their structure
alkyl dihalide - Correct Answer The product of adding halogens to an alkene is an alkyl dihalide.
alkyl halide (haloalkane) - Correct Answer The product of radical halogenation of an alkane
Alkynes (also called acetylenes) - Correct Answer Hydrocarbon molecules that contain one or more C≡C (triple)
bonds in their structure
Allotropes - Correct Answer Allotropes are different physical forms in which an element can exist.
angle strain - Correct Answer The strain that occurs when bond angles deviate from their ideal values by being
stretched or compressed.
Angle strains are also a potential for energy. The more angle strain there is the more potential energy there is. Small
cycloalkane rings (3-5 carbons) are high in potential energy and very reactive because they have more angle strain.
As the ring gets bigger (more carbon atoms), the C-C-C bond angle of the ring also gets larger and the angle strain
decreases.
Are alkenes and alkynes saturated or unsaturated? - Correct Answer unsaturated hydrocarbons
Meaning that they have a lower hydrogen-to-carbon ratio than their saturated hydrocarbon counterparts.
aromatic hydrocarbons - Correct Answer The second major class of hydrocarbon molecules.
, While still composed of only carbon and hydrogen atoms, undergo a very different and specific set of reactions that
set them apart as a unique class of hydrocarbon molecules. In fact, aromatic hydrocarbons are noted for their stability
and overall lack of reactivity.
The term aromatic applies only to the chemical and physical properties of this class of hydrocarbons. As a class,
aromatic hydrocarbons are also referred to as -arenes.
As the molecular weight of alkanes increases what happens to MP and BP? - Correct Answer The MP and BP
increase as well
Because of the locked planar nature of C=C bonds, can there be trans or cis stereoisomers of those groups? -
Correct Answer They can have stereoisomers but they have to exist as two separate compounds (a compound
cannot convert due to the locked nature). The stereoisomers cannot be interconverted by rotation around the C-C
bond and so exist as two unique compounds.
These compounds have different physical and chemical properties and a mixture of these two can be separated by
various laboratory methods like distillation - a method for separating compounds based on differences in boiling
points.
Carbocyclic (or cyclic) compounds - Correct Answer Molecules whose carbon skeletons contain one or more rings of
carbon atoms. The rings may contain multiple bonds and have chains (or branched chains) of carbon atoms attached
to them. Many compounds with more than one ring are known.
chair conformation - Correct Answer The most stable conformation of cyclohexane, with one part puckered upward
and another part puckered downward.
The advantage of the chair conformation is that there is no ring strain in the cyclohexane molecule. The C-C-C bond
angles are very close to the ideal tetrahedral angle (so no angle strain), and in addition, the non-planarity allows for
all the hydrogens on any C-C bond to exist in a staggered conformation (no torsional strain).
Cis/trans stereoisomers - Correct Answer Stereoisomers in which substituents are positioned on the same (cis) or
opposite (trans) side of the plane of the ring. (So they are not moving which carbon they are on, they are just moving
which side of the plane they are residing on - they can be on the same plane or opposite planes)
Combustion (Oxidation) in relation to alkanes - Correct Answer The most important reaction of alkanes is the ability to
use them as fuel in a combustion reaction. Burning alkanes in an oxygen environment produces not only the chemical
products carbon dioxide and water but also energy in the form of heat (thermal energy). The combustion of alkanes is
an oxidation process since carbon is combining with oxygen.
conformations - Correct Answer Different orientations of atoms or groups of atoms because of rotation around a
single bond (the rotations occur like wheels on an axle, with the sigma bond being the axle).
Alkanes can adopt different conformations because of rotation around a C-C sigma bond).
conformers - Correct Answer Different shapes of molecules derived by rotations of single bonds.
Conformers are different forms of a single molecule that can be interconverted by rotation around single (sigma)
bond.
Cycloalkanes - Correct Answer Alkanes whose carbon skeleton forms a ring.
Also only has single C-C bonds.
delocalized network of p orbital electrons - Correct Answer Each of the six carbon atoms on benzene is sp2
hybridized, resulting in bond angles of 120° and a trigonal planar geometry. Each carbon also possesses a single,
unhybridized p orbital. Due to the cyclic structure, the individual p orbitals on each carbon contribute a single electron
to the pi system (delocalized network) by sideways overlap of its p orbital with those of its neighboring carbons. This
delocalization allows the pi electrons to be spread out over all six carbons in the ring.
eclipsed conformation - Correct Answer a conformation about a carbon-carbon single bond in which the atoms or
groups on one carbon are as close as possible to the atoms or groups on an adjacent carbon
electrophile - Correct Answer A chemical species that seeks electrons. Electrophiles themselves are electron-
deficient and possess a (+) electrical charge or a +.
Acyclic compounds - Correct Answer Molecules whose skeletons do not contain any rings. The carbon chains of
acyclic molecules can be linear or branched and may consist of alkanes, alkenes, or alkynes.
Addition of Acids to Alkenes/Alkynes - Correct Answer When acids (HCl, HBr, HI, HF, and H-OSO3H [sulfuric acid])
are added to alkenes or to alkynes.
Acids have the general structure of H-A, where H is the acidic proton (the proton typically donated or released when
the molecule acts as an acid) and "A" represents the rest of the molecule to which the acidic H is attached. When an
acid reacts with an alkene, the H is added to one carbon, and the "A" (the remainder of the acid) becomes attached
to the other carbon.
addition reaction - Correct Answer An addition reaction adds atoms or groups of atoms to each carbon of the multiple
bond (they are added across the double bond). As they bond to each carbon it causes the double bond between the
carbons to become a single bond.
The most common reaction for alkenes and alkynes.
Addition reactions can also be viewed as combination reactions since two different molecules (alkene substrate and
another molecule) join to form a single new compound.
alcohol - Correct Answer The product of the hydration of an alkene is an alcohol - an organic molecule containing the
hydroxyl (-OH) functional group.
aliphatic hydrocarbons - Correct Answer The first major class of hydrocarbon molecules, made up of by alkanes,
alkenes, and alkynes
Alkanes - Correct Answer A type of hydrocarbon that are considered a saturated hydrocarbons because the skeleton
is composed of only C-C single bonds.
Alkenes (also called olefins) - Correct Answer Hydrocarbons with one or more C=C (double) bonds in their structure
alkyl dihalide - Correct Answer The product of adding halogens to an alkene is an alkyl dihalide.
alkyl halide (haloalkane) - Correct Answer The product of radical halogenation of an alkane
Alkynes (also called acetylenes) - Correct Answer Hydrocarbon molecules that contain one or more C≡C (triple)
bonds in their structure
Allotropes - Correct Answer Allotropes are different physical forms in which an element can exist.
angle strain - Correct Answer The strain that occurs when bond angles deviate from their ideal values by being
stretched or compressed.
Angle strains are also a potential for energy. The more angle strain there is the more potential energy there is. Small
cycloalkane rings (3-5 carbons) are high in potential energy and very reactive because they have more angle strain.
As the ring gets bigger (more carbon atoms), the C-C-C bond angle of the ring also gets larger and the angle strain
decreases.
Are alkenes and alkynes saturated or unsaturated? - Correct Answer unsaturated hydrocarbons
Meaning that they have a lower hydrogen-to-carbon ratio than their saturated hydrocarbon counterparts.
aromatic hydrocarbons - Correct Answer The second major class of hydrocarbon molecules.
, While still composed of only carbon and hydrogen atoms, undergo a very different and specific set of reactions that
set them apart as a unique class of hydrocarbon molecules. In fact, aromatic hydrocarbons are noted for their stability
and overall lack of reactivity.
The term aromatic applies only to the chemical and physical properties of this class of hydrocarbons. As a class,
aromatic hydrocarbons are also referred to as -arenes.
As the molecular weight of alkanes increases what happens to MP and BP? - Correct Answer The MP and BP
increase as well
Because of the locked planar nature of C=C bonds, can there be trans or cis stereoisomers of those groups? -
Correct Answer They can have stereoisomers but they have to exist as two separate compounds (a compound
cannot convert due to the locked nature). The stereoisomers cannot be interconverted by rotation around the C-C
bond and so exist as two unique compounds.
These compounds have different physical and chemical properties and a mixture of these two can be separated by
various laboratory methods like distillation - a method for separating compounds based on differences in boiling
points.
Carbocyclic (or cyclic) compounds - Correct Answer Molecules whose carbon skeletons contain one or more rings of
carbon atoms. The rings may contain multiple bonds and have chains (or branched chains) of carbon atoms attached
to them. Many compounds with more than one ring are known.
chair conformation - Correct Answer The most stable conformation of cyclohexane, with one part puckered upward
and another part puckered downward.
The advantage of the chair conformation is that there is no ring strain in the cyclohexane molecule. The C-C-C bond
angles are very close to the ideal tetrahedral angle (so no angle strain), and in addition, the non-planarity allows for
all the hydrogens on any C-C bond to exist in a staggered conformation (no torsional strain).
Cis/trans stereoisomers - Correct Answer Stereoisomers in which substituents are positioned on the same (cis) or
opposite (trans) side of the plane of the ring. (So they are not moving which carbon they are on, they are just moving
which side of the plane they are residing on - they can be on the same plane or opposite planes)
Combustion (Oxidation) in relation to alkanes - Correct Answer The most important reaction of alkanes is the ability to
use them as fuel in a combustion reaction. Burning alkanes in an oxygen environment produces not only the chemical
products carbon dioxide and water but also energy in the form of heat (thermal energy). The combustion of alkanes is
an oxidation process since carbon is combining with oxygen.
conformations - Correct Answer Different orientations of atoms or groups of atoms because of rotation around a
single bond (the rotations occur like wheels on an axle, with the sigma bond being the axle).
Alkanes can adopt different conformations because of rotation around a C-C sigma bond).
conformers - Correct Answer Different shapes of molecules derived by rotations of single bonds.
Conformers are different forms of a single molecule that can be interconverted by rotation around single (sigma)
bond.
Cycloalkanes - Correct Answer Alkanes whose carbon skeleton forms a ring.
Also only has single C-C bonds.
delocalized network of p orbital electrons - Correct Answer Each of the six carbon atoms on benzene is sp2
hybridized, resulting in bond angles of 120° and a trigonal planar geometry. Each carbon also possesses a single,
unhybridized p orbital. Due to the cyclic structure, the individual p orbitals on each carbon contribute a single electron
to the pi system (delocalized network) by sideways overlap of its p orbital with those of its neighboring carbons. This
delocalization allows the pi electrons to be spread out over all six carbons in the ring.
eclipsed conformation - Correct Answer a conformation about a carbon-carbon single bond in which the atoms or
groups on one carbon are as close as possible to the atoms or groups on an adjacent carbon
electrophile - Correct Answer A chemical species that seeks electrons. Electrophiles themselves are electron-
deficient and possess a (+) electrical charge or a +.
