Alkanes and Conformational Isomers of Alkanes Flashcards
What are alkanes? What is the formula?
Compounds with C-C and C-H single bond.
Cn H2n+2
What is the formula for methane
C1H4
What is the formula for ethane?
C2H6
What is the formula for propane?
C3H8
What is the formula for butane?
C4H10
What is the relationship between an alkane’s size and its boiling point and melting point?
boiling point and melting point increase as size of alkane increases directly proportional to the increase in dispersion force
IN ISOMERS:
more branched means less surface area means less boiling point for isomers
What is the parent chain name for C1H4
meth
What is the parent chain name for C2H6
Eth
What is the parent chain name for C3H8
Prop
What is the parent chain name for C4H10
But
What is the parent chain name for C5H12
Pent
What is the parent chain name for C6H14
Hex
What is the parent chain name for C7H16
Hept
What is the parent chain name for C8H18
Oct
What is the parent chain name for C9H20
Non
What is the parent chain name for C10H22
Dec
What is a straight chain alkane?
Carbon atoms connected to no more than 2 other carbons
- continuous chain
Ex: butane and pentane
What is a branched like alkane?
carbon atoms connected to 3 or 4 carbon atoms
Ex: isobutane and isopentane
What are alkyl group?
Partial structure that remains after the removal of one H from an alkane
- parts of a larger molecule
What is the name replacement at the end of an alkyl group?
“ane” ending of alkane with “-yl” ending
Ex: methane (CH4) to methyl (CH3-)
Why is rotation possible around C-C bond in alkanes?
Alkanes are cylindrically symmetrical
What is a confirmation?
Different arrangements of atoms that results from bond rotation
Which configuration is the most stable?
Staggered Confirmation
The confirmation that position all six C-H in an ethane as far away from one another as possible;
- lowest energy
Which configuration is the least stable?
Eclipse Confirmation
The confirmation in which all six C-H bond in an enthane are as close as possible
- highest energy
What is torsional strain?
Strain in a molecule caused by electron repulsion between eclipsed bond
What is an anti confirmation?
Confirmation in which the two methyl group in a butane are as far apart as possible- 180 degree apart
What is a gauche confirmation?
Confirmation in which the two methyl group are 60 degree apart
What is a steric chain?
repulsive interaction caused by a gauche confirmation that occur when atoms are forced closer together than their atomic radii allow
What is a partially eclipsed confirmation?
Confirmation of butane in which the two methyl groups are 120 degrees apart , but all bond overlap
What is a fully eclipsed confirmation?
Confirmation of butane in which the two methyl groups are 0 degrees apart
What is a primary carbon?
Carbon attached to only one carbon
What is a secondary carbon?
Carbon attached to 2 carbon
What is a tertiary carbon
Carbon that is attached to three carbon
What is a quaternary carbon?
Carbon attached to 4 carbon
What is a stereoisomer?
Compounds which have their atoms connected in the same order but differ in 3-D orientation
What is a constitutional isomer?
Same molecular compounds with the same molecular formula
