Org 1 Review - Structure and Bonding

xomatude's version from 2017-03-15 23:18

Section 1

Question Answer
Under what circumstances does the "octet rule" get broken?Octet rule can be broken for sulfur, phosphorus, and other atoms in the second row and below that can incorporate d orbitals into their bonding.
When considering which Lewis structure (or resonance form) is most stable for a given molecule, the most stable will be one in which ____ is minimized. Resonance structures with less charge separation are more stable.
In chemical reactions we draw curved arrows going from areas of _____ electron density to _____ electron density. Curved arrow goes from areas of high electron density to areas of low electron density.
What's a "conjugate base" and a "conjugate acid"?Conjugate base - structure where we have removed a proton (H+). Conjugate acid - structure where we have added a proton. Conjugate base of H2O is HO(-). Conjugate acid of water is H3O(+).
Take the reaction of HO(-) with H+ . When drawing the curved arrow, we would draw the tail of the arrow from the _____ and the head of the arrow towards the ____. Curved arrows depict electron flow. Draw tail at the HO(-) (the source of the electrons) and the head of the arrow to the H(+).
What is a key principle for determining whether an acid-base reaction will happen or not?General principle is, "Stronger acid plus stronger base gives weaker acid and weaker base".
When a bond breaks so as to give two electrons to one atom and zero electrons to another atom, this is _______ cleavageWhen it breaks unequally this is heterolytic cleavage.
When a bond breaks so as to give one electron to each atom of the bond, this is called ______ cleavage.When it breaks equally this is homolytic cleavage.
The predominant source of strain in molecules such as cyclopropane and cyclobutane is _______ strainThe predominant source of strain in these molecules is angle strain or baeyer strain. It arises since the bonds in these molecules must deviate far from their ideal angle of 109 degrees; this creates strain.
Another name for (1,methylethyl) is ______ 1methylethyl = isopropylAnother name for (1,methylethyl) is ______ 1methylethyl = isopropyl

Section 2

Question Answer
Another name for (2,2-dimethylethyl) is _____2,2,-dimethylethyl = t-butyl
How does acidity change as you go down the periodic table? As you go down, acidity increases - so H2S is more acidic than H2O for instance.
How does acidity change as you go across the periodic table? As you go across (to the right) acidity increases - so HF is more acidic than H2O which is more acidic than NH3 etc.
What does "aliphatic" mean? Aliphatic essentially means "not aromatic". Aromaticity tends to be an Org 2 topic.
Another name for "cis" 2-butene is "___"-butene [E or Z?] (Z)- 2-butene
When two p orbitals combine to form a pi bond, two molecular orbitals are created. the lowest energy one is the ____ and the high energy one is the ____. [Remember- we don't care at all about the s orbitals here Lowest energy is HOMO, lowest energy is LUMO. The electrons are in the HOMO (highest occupied molecular orbital).
Rank the strengths of the following bonds: primary C-H secondary C-H tertiary C-H. Which C-H bond will be strongest and which will be weakest?primary C-H > secondary C-H > tertiary C-H
In an alcohol, (e.g. CH3-OH)for the O-H bond, the ______ atom will be delta negative and the _____ will be delta positive. hydrogen is delta positive, oxygen is delta negative
What is less electron donating, alkyl groups or hydrogens? Hydrogens are less electron donating.
How are 1-butanol and 2-butanol related to each other? .1-butanol and 2-butanol are configurational isomers (aka constitutional isomers)

Section 3

Question Answer
What's the difference between "proton", "hydrogen atom", and "hydride"? Proton - refers to the cation of H(+). Hydrogen atom refers to the neutral species with one electron (H•). "Hydride" refers to the anion of hydrogen with two electrons, H(-).
In the B-H bond, which atom is delta negative and which is delta positive? The electronegativity of B is 2.0 and that of H is 2.2, so the hydrogen is delta negative and the boron is delta positive.
Why do alcohols have higher boiling points than ethers (of the same molecular weight)?Alcohols have higher boiling points because they can hydrogen bond with themselves, and hydrogen bonding is a strong interaction.
What's the relationship between charge and acidity? Acidity increases as you increase the charge. So H3O(+) is a stronger acid than H2O.
What is the geometry/hybridization of a carbocation? Sp2 hybridized - trigonal planar (flat)
What's the geometry of carbons with the following hybridization: sp3 sp2 spsp3 = tetrahedral, sp2 = trigonal planar, sp = linear
A Lewis acid ____ a pair of electrons, while a Lewis base _____ a pair of electrons. a Lewis acid accepts a pair of electrons, a Lewis base donates a pair of electrons.
What do 'allylic" and "benzylic" mean? Allylic - the position next to a double bond. Benzylic - the position next to an aromatic ring.
For each of these bonds identify which end is positive and which is negative O=C Br-C Na-OCH3 Mg-C Li-N Cl-Al O=C oxygen negative, carbon positive Br-C bromine negative, carbon positive NaOCH3 sodium positive, oxygen negative Mg-C magnesium positive, carbon negative Li-N lithium positive, nitrogen negative Cl-Al chlorine negative, aluminum positive.


Org 1 Review - Thermodynamics
Org 1 Review - Free Radicals
Org 1 Review - Reactions of Alcohols
Org 1 Review - Alkynes
Org 1 Review - Substitution and Elimination
Org 1 Review - Reactions of Double Bonds
Org 1 Review - Stereochemistry
Org 1 Review - Conformations