Chemistry Chapter 9: Organic Chemistry Basics Flashcards
Stereocenter
refers to any atom in a molecule that gives rise to stereoisomers when its substituents are rearranged or interchanged
Are all stereocenters chiral?
NO. For example, CIS/Trans alkenes are stereocenters because rearranging the H and the methyl group produces a trans (so these are diastereomers)
CIS/Trans are examples of what kind of isomerism?
Diastereomers
Are all chiral centers also stereogenic?
YES
Naming with E/Z
Each substituent on the double-bonded carbons is assigned a priority based on atomic number:
Higher atomic number = higher priority.
If there is a tie, you move outward along the chain until the tie is broken.
Zaitsev’s rule states
that the more substituted alkene will form in preference to the less substituted molecule. So, generally, the more substituted a double bond is, the more stable the alkene will be.
more substituted = more stable
Hückel’s Rule for Aromaticity
molecule is aromatic if it has (4n + 2) π-electrons, where n is any integer (0, 1, 2, 3, …).
Conditions for Aromaticity:
For a molecule to be aromatic, it must satisfy all of these conditions:
Cyclic – The molecule must be a ring.
Planar – The ring must be flat (planarity allows π-electrons to delocalize).
Fully conjugated – Every atom in the ring must have a p-orbital, allowing continuous electron delocalization.
Follow Hückel’s rule – It must have (4n + 2) π-electrons.
Constitutional isomers vs stereoisomers
Constitutional isomers: same formula different connectivity
Stereoisomers: same formula, same connectivity, different arrangement
Difference between electron withdrawing groups and electron donating groups
EWG = pull electron density away from C attached
EDG = donate electron density to the C attached
ie OH is a EWG group on an alkyl chain (more electro negative) but is a EDG on an aromatic ring (donates e density to conjugated delocalized system)
Alkane formula
Alkene formula
Alkyne formula
Cycloalkane, cycloalkenes and cycloalkyne formula
Is this compound aromatic?
Yes, follows huckel’s rule (4n + 2 pi electrons). It has 4 e from double bond and oxygen contributes 1 lone pair.
Oxygen in furan is sp² hybridized because the ring must be planar and fully conjugated for aromaticity.
This means oxygen has three sp² hybridized orbitals and one unhybridized p orbital.
so it has 6 pi electrons
What are the chemical formulas each time phosphoric acid loses a proton?
H3PO4
H2PO4-
HPO42-
PO43-
Phosphorous acid
H₃PO₃
is a cyclic ester formed by the intramolecular condensation of a hydroxy acid (a molecule containing both a hydroxyl group (-OH) and a carboxyl group (-COOH)).
lactone
