Organic Chemistry Chapter 4 – Flashcards
Unlock all answers in this set
Unlock answersquestion
alkanes and cycloalkanes are hydrocarbons in which all the
answer
carbon-carbon bonds are single bonds
question
hydrocarbons that contain carbon double bonded to carbon is an
answer
alkene
question
hydrocarbons that contain carbon triple bonded to carbon is an
answer
alkyne
question
formula for alkanes is
answer
CnH2n+2
question
formula for cycloalkanes is
answer
CnH2n
question
what type of hybridization and shape do alkanes and cycloalkanes have
answer
sp3 tetrahedral
question
even "straight chain" alkanes are not straight they have a
answer
zigzag geometry
question
examples of straight chain unbranched alkanes are
answer
butane and pentane
question
examples of branched chain alkanes are
answer
isobutane and neopentane
question
butane and isobutane have same molecular formula (C4H10) but have different bond connectivities so they are
answer
constitutional isomers
question
the # of constitutional isomers increases rapidly with
answer
the number of carbons
question
constitutional isomers usually have different
answer
physical properties
question
why do constitutional isomers have diff physcial props
answer
as we change change we change intermolecular forces which changes properties diff SA=diff intermolec forces
question
most commonly used nomenclature system is the
answer
IUPAC system
question
what is the common name for 2-propanol
answer
isopropanol
question
1st rule of naming branched-chain alkanes is
answer
use longest continuous carbon as parent name
question
2nd rule of naming branched-chain alkanes is
answer
use the lowest number of the sustitiuent
question
3rd rule of naming branched-chain alkanes is
answer
use number obtained by rule 2 to designate location of substituent
question
4th rule of naming branched-chain alkanes is
answer
for 2 or more sub use lowest individual number of parent chain, sub listed in alphabetical order disregarding multiplying prefixes such as di and tri
question
5th rule of naming branched-chain alkanes is
answer
when 2 sub identical on same carbon use that number twice
question
6th rule of naming branched-chain alkanes is
answer
for identical sub use prefixes such as di, tri, tetra, ect
question
7th rule of naming branched-chain alkanes is
answer
2 chains with equal length compete for parents chain choose one with greater number of subs
question
8th rule of naming branched-chain alkanes is
answer
when branching first occurs at equal distance from either end of longest chain, choose name that gives lower number at the first point of difference
question
we classify hydrogen atoms by
answer
what they are connected too
question
halogens are treated as
answer
substituents with prefix such as fluor, chloro, bromo, iodo
question
naming alcohols you select longest continuous chain to which the what is directly attached? how do you change name of alkane
answer
hydroxyl change -e to -ol
question
number longest carbon chain that gives carbon bearing the OH the what? indicate what of OH?
answer
lower number position
question
what prefix do you attach to cycloalkanes with only one ring
answer
cyclo-
question
when more then one ring system is attached to a single chain you name it is
answer
dicyclo
question
bicycloalkanes are alkanes containing
answer
two fused or bridged rings
question
when naming alkenes begin numbering at the end of chain closest to
answer
carbon carbon double bond
question
naming alkenes assign location of carbon double bond by
answer
using number of first atom of carbon double bond as the prefix
question
naming alkenes indicate locations of the substitiuent groups by the numbers of the
answer
carbon atoms to which they are attached
question
naming alkenes number substituted cycloalkenes in way that gives carbon atoms of double bond the (2 things)
answer
1 and 2 position and sub groups lower numbers at first point of difference
question
name compounds containing double bond and alcohol group as alkenols and give alcohol carbon the
answer
lower number
question
two identical or sub groups on same side of carbon double bond is
answer
cis
question
two identical or sub groups on opposite sides of carbon double bond i
answer
trans
question
alkynes named in same way as alkenes except
answer
ending name is changed to -yne
question
OH group has priority over
answer
carbon triple bond
question
two groups bonded by a single bond can undergo (with respect to each other)
answer
rotation about that bond
question
temporary molecular shapes that result from a rotation about a single bond
answer
conformations
question
each possible structure of conformation
answer
conformer
question
analysis of energy changes that occur as a molecule undergoes rotations about single bond
answer
conformational analysis
question
cycloalkanes do not have the same relative stability due to
answer
ring strain
question
ring strain comprises
answer
angular and torsional strain
question
result of deviation from idea bond angles caused by inherent structural constraints
answer
angular strain
question
result of dispersion forces that cannot be relieved due to restricted conformational stability
answer
torsional strain
question
cyclobutane ring is not planar but is actually slightly
answer
folded
question
what type of conformation does cyclopentane have
answer
slightly bent
question
what are the two conformers of cyclohexane
answer
chair and boat form
question
what conformation of cyclohexane is less stable and why
answer
boat higher energy
question
what conformation has lower energy than pure boat form conformation and how stable is this conformation compared to the chair form
answer
twist boat and not as stable as chair form
question
what ring is most commonly found in nature
answer
6 membered ring
question
the chair conformation of cyclohexane has two distinct orientations for the bonds that project from the ring which are termed as
answer
axial and equatorial
question
axial hydrogen atoms are either
answer
up or down in a vertical column
question
equatorial hydrogen atoms are
answer
all angled slightly
question
when drawing chair conformational structures try to make corresponding bonds
answer
parallel in your drawing
question
for methylcyclohexane the chair conformation with axial G is less stable due to
answer
1,3-diaxial interaction
question
the larger the G group the more severe the (2 parts)
answer
1,3-diaxial interaction and shifted of equilibrium from axial G form chair to equatorial
question
the chair conformation with what group is less stable due to 1,3-diaxial interaction
answer
axial tert-butyl group
question
upper lower bonds means the groups are
answer
trans
question
alkanes, as a class, are characterized by general
answer
inertness to many chemical reagents
question
C-C and C-H bonds are quite (how do they break?)
answer
strong only break when alkanes heated to very high temps
question
because C and H atoms have nearly same EN the C-H bonds of alkanes are only
answer
slightly polarized
question
this low reactivity of alkanes toward reagents accounts for the fact that alkanes were originally called what? what does this name mean
answer
paraffins little affinity
question
the difference in the number of pairs of hydrogen atoms between the compound under study and an acyclic alkane having the same number of carbons
answer
index of hydrogen deficiency
question
each double bond or ring for saturated acyclic alkanes
answer
has 2 hydrogens less
question
each double bond or ring provides
answer
one unit of hydrogen deficiency
question
when calculating IHD for compounds containing halogens count atoms as though they are
answer
hydrogen atoms
question
when calculating IHD for compounds containing oxygen
answer
ignore oxygen atoms and calc IHD from remainder of formula
question
when calculating IHD for compounds containing nitrogen
answer
subtract one hydrogen from each nitrogen atom and ignore nitrogen atoms
question
nature perfers states of
answer
lower PE
question
steric factors (spatial factors) can affect the
answer
stability and reactivity of molecules
question
like charges
answer
repel