Exam #2 Flashcards
What is an alkane?
- saturated hydrocarbons
- no double or triple bonds
- lack functional groups
What is a cycloalkane?
cyclic hydrocarbons
What are the four steps of IUPAC naming?
- finding the parent chain
- identify and name substituents
- number parent chain and assign locate to each substituent
- arrange substituents alphabetically
How is stability of alkanes determined?
- measured by heat of combustion
- branched alkanes are more stable (have lower heat of combustion
Optically active definition.
compounds rotate plane-polarized light
(+)Rotation
dextroratory
(-)Rotation
Levoratotory
If compound A is R and (+)
then, its S enantiomer is (-)
If compound B is S and (+)
then, its R enantiomer is (-)
Which one is optically active, chiral or achiral?
optically active- chiral
optically inactive - achiral
Diastereomers
stereoisomers that are not mirror images
nonsuperimposable
Enantiomers
nonsuperimposable mirror images
Stereoisomers
same connectivity, non superimposable
Meso Compounds
contain an internal plane of symmetry
Atropisomers
compounds that have restricted rotation around a single bond, trapped in conformation
Ex: Biphenyls and Allenes
Why is a chair conformation more stable than a boat conformation if they both have a bond angle of 109 degrees?
a boat conformation has torsional strain
racemic mixture
a mixture of equal quantities of two enantiomers, or substances that have dissymmetric molecular structures that are mirror images of one another.
What is mass spectroscopy?
- Not a form of traditional spectroscopy, doesn’t use electromagnetic radiation
- Bombards simple with electrons
- Primary Use: determine molecular weight and molecular formula
What can mass spectroscopy be used for?
- forensic science
- drug development
- protein science
What occurs in a mass spectrometer?
- a compound is vaporized, then ionized, and undergoes fragmentation
- The masses of the ions are detected and graphed
-> High energy electrons collide with a molecule and produce a radical cation by displacing an electron
Molecular Ion (M)*+ - The radical cation
- +1 charge on the radical cation
- no change in mass
- splits into an uncharged radical and carbocation (fragmentation)
What is the base peak?
the tallest peak
The (M)*+ Peak
- Has the full mass of the parent compound
- can be base peak if it is stable
- If peak has an odd m/z, likely contains nitrogen
