Organic Chemistry Flashcards
What are structural isomers?
Molecules that have the same molecular formula, but different connectivity of atoms.
What are geometric isomers?
Molecules that share a molecular formula and basic connectivity of atoms, but have atoms arranged differently in space (due to a ridged double carbon-carbon bond that cannot rotate on its axis).
If two of a certain functional group are on the same side of a double C=C bond, it is a…
Cis isomer.
If two of a certain functional group are on different sides of a double C=C bond, it is a…
Trans isomer.
Do alkanes have a low or high boiling point? Why?
They have a low boiling point, because the molecules are non-polar (C-H bonds and C-C bond are non-polar), so temporary dipoles are intermolecular forces. These take little energy to overcome, so the boiling point of an alkane is low.
Are haloalkanes polar? Why?
The halogen-carbon bond is electronegative, creating a charge difference (dipole) and polarity. This charge and the large weight of the atom gives haloalkanes higher boiling points than alkanes, alkenes, and alkynes.
Can alkynes produce geometric isomers?
No, they cannot, as although the triple carbon-carbon bond is ridged and cannot rotate on its axis, more valence electrons are taken up in making this bond, so each C atom involved only bonds to one other atom, meaning the arrangement of atoms in space is irrelevant.
What does the term “tertiary alcohol” mean?
An alcohol where the hydroxyl group is bonded to a carbon bonded to three other carbons.
What does the term “secondary amine” mean?
An amine where the nitrogen is bonded to two carbon atoms (not bonded to a carbon to two other carbons, like alcohols or haloalkanes)
What of all of the organic functional groups has the highest average boiling point, and why?
Carboxylic acids, because of the combination of the weight of the oxygen and hydroxyl group, and the large dipole produced by the C-OH bond and the C=O bond. Much energy is needed to overcome these forces.
Alkynes and alkenes have slightly higher boiling points than alkanes. Why is this?
The double and triple bonds of the unsaturated hydrocarbons are a region of electron density, which creates a dipole and stronger attractive forces between molecules. The difference in boiling point is only marginal, however.
What is Markovnikov’s rule?
In addition reactions, carbon atoms with more hydrogen atoms tend to accept hydrogen atoms (for example in halohydrogenation). Products that follow this rule will be the major product.
What is Zaitzev’s rule?
In elimination reactions, carbon atoms with fewer hydrogens bonded to them tend to lose their hydrgoens. The compound that follows this rule will be the major product.
If you combine bromine water with saturated and unsaturated hydrocarbons, what would you expect to happen?
You would expect to see the unsaturated hydrocarbons (like alkynes and alkenes) decolourise the brown bromine water quickly, producing a colourless dibromoalkane (addition). If UV light is present, the saturated hydrocarbon will decolourise the bromine water, producing a bromoalkane (substitution).
If you combined acidified dichromate with a primary, secondary, and tertiary alcohol, what would you expect to happen?
No reaction would occur between the tertiary or secondary alcohols and the dichromate. The primary alcohol would be oxidised and be a carboxylic acid. The orange dichromate would become green from chromium ions.
