achieve 1-5 midterm practice

Organic chem

1- longest bond?

2- shortest bond?

3-strongest?

4-weakest?

1-D

2-A

3-A

4-D

The greater the number of electrons involved in bond formation (the greater the bond order), the stronger the bond.

A triple bond (bond order equals 3, with six bonding electrons) has more bonding electrons than a double bond (bond order equals 2, with four bonding electrons), which has more bonding electrons than a single bond (bond order equals 1, with two bonding electrons).

Recall that bond strength increases as bond length decreases.

Bond A, a triple bond, is the strongest and shortest bond. This bond has more bonding electrons (six) than Bond B, a double bond, and Bonds C and D, which are both single bonds.

predict molecular shape of

methane?

carbonate ion?

carbon dioxide

sulfite ion

tetrahedral

trigional planar

linear

trigional pyramidal

tetrahedral

formal charge of N?

formal charge of B?

N- +1

B- -1

formal charge= valence electrons-(bonds +dots)

Both an −NR3 and −NHR2 groups are amine groups. If the nitrogen was bonded to a carbonyl group (C=O), then it would be an amide functional group.

An −OH group is a hydroxy or hydroxyl group and is found in alcohols. An ether group consists of an oxygen bonded to two alkyl carbons.

A chlorine is a halo group. Other halides include fluorine (F), bromine (Br), and iodine (I).

a,b,c,d?

a- ketone

b-ether

c-amide

d- amine

aldehyde

alcohol

aldehyde( c=o with at least 1 hydrogen atom attached)

The highest mass in a mass spectrum is generally the molecular ion peak. The molecular ion and the molecule differ by an electron only, so they have the same mass. Thus, this compound has a molecular mass of 86 amu.

The mass of C2H3O is 43 amu (half the molecular mass), so the subscripts in the empirical formula should be multiplied by 2. The molecular formula of the compound is C4H6O2.

There are several plausible structures for this compound. The first structure should contain some combination of the functional groups alcohol (−OH), ether (C−O−C), and alkyne (C≡C). The second structure will contain two C=O groups, one on a terminal carbon atom (aldehyde) and one on a non‑terminal carbon atom (ketone).

CH₃CH₂NHCHCH₂

(CH₃)₃CCH₂Cl

what is the difference between 2 resonance structures?

same molecular formula, arrangements of atoms, different arrangements of electrons

Compounds with different molecular formulas are not related.

Compounds with the same molecular formula, but a different arrangement of atoms are constitutional isomers.

Compounds that have the same molecular formula, same arrangement of atoms, but differ only in rotation are conformational isomers.

curved arrow can start from?

a pie bond or electron pair

The top carbon atom has four groups bonded to it, three H atoms and one C atom, and it has 𝑠𝑝3 hybridization.

The two carbon atoms that share the double bond each have three groups bonded to them. They each have 𝑠𝑝2 hybridization.

The second carbon atom from the bottom has four groups bonded to it, two H atoms and two C atoms. It has 𝑠𝑝3 hybridization.

The bottom carbon atom has four groups bonded to it, three H atoms and one C atom, and it has 𝑠𝑝3 hybridization.

lewis base requires

a lone pair of electrons

base= donor

lewis acid requires

empty orbital

acid=accept

bronsted theory of acid

proton donor

bronsted theory of bases

proton acceptor

most soluable in water?

O OH, non polar

alkanes are not soluble

the __ projection is the most stable

staggered

local energy min

molecule is most stable point compared to surroundings (ex: in gauche)

global energy min

lowest energy among all conformations ex: anit conformation

gauche conformation

two big groups next to each other, max separated

antistag

two big groups opposite sides

lowest stability conformation

eclipsed

trans

Keep in mind that trans groups are on opposite faces of the ring.

angle strain

3 & 4 membranes rings

steric strain

close proximity of electrons of bulky groups

torsional strain

single bond that rotates from staggered to eclipse

cis

same side of the ring

more stable conformation cis/trans

cis-more stable conformation is the one in which the larger group is in the equatorial position.