Organic Chemistry Exam 1

Chapters 1-4

Provide electron configuration of carbon atom in the ground state. (Standard notation)

[C]1s^22s^22p^2

Which orbital has the following quantum numbers: n = 2, l = 1, m_l = 0

a) 1s b) 2s c) 2p_z d) 3d_xy

c

What is the common charge of a magnesium ion?

+2

An atom has the electronic configuration 1s²2s²2p⁶3s²3p⁵. What ion is it most likely to form?

a) -2 b) -1 c) +1 d) +2

b

Use either signs δ+ and δ-, or arrows, to indicate polarity of each bond in the compounds shown below.

H₃C—OH

δ+; δ-

Use either signs δ+ and δ-, or arrows, to indicate polarity of each bond in the compounds shown below.

H₃C—MgBr

δ-; δ+

Use either signs δ+ and δ-, or arrows, to indicate polarity of each bond in the compounds shown below.

H₂C=NH

δ+; δ-

Define an orbital

a region of space in which the probability of finding an electron is 90%

Electron affinity is an energy that is released when a ? ion is formed (when an atom gains an ?) and is an experimentally determined quantity

negative; electron

Electronegativity is a ? concept and it represents an ability to attract a ? electron pair.

theoretical; shared

How many valence electrons does a phosphorus atom have?

5

Classify each of the following compounds as ionic or covalent. If one of the bonds in a molecule is ionic, the compound is classified as ionic. Only if all the bonds are covalent, the compound is considered to be covalent.

CsCl

ionic

Classify each of the following compounds as ionic or covalent. If one of the bonds in a molecule is ionic, the compound is classified as ionic. Only if all the bonds are covalent, the compound is considered to be covalent.

CaCl₂

ionic

Classify each of the following compounds as ionic or covalent. If one of the bonds in a molecule is ionic, the compound is classified as ionic. Only if all the bonds are covalent, the compound is considered to be covalent.

NO₂

polar covalent

Classify each of the following compounds as ionic or covalent. If one of the bonds in a molecule is ionic, the compound is classified as ionic. Only if all the bonds are covalent, the compound is considered to be covalent.

CH₃MgBr

ionic

Classify each of the following compounds as ionic or covalent. If one of the bonds in a molecule is ionic, the compound is classified as ionic. Only if all the bonds are covalent, the compound is considered to be covalent.

HClO

polar covalent

electronegativity difference of 1.7 and above is ?

ionic

electronegativity difference of 0.2-1.7 is ?

polar covalent

electronegativity difference of 0.2 and below is ?

nonpolar covalent

In which of the following compounds does carbon have a partial positive charge?

a) H₃C-Li

b) H₃C-Br

c) H₃C-SiH₃

d) H₂B-CH₃

b

What are the formal charges for these atoms?

1;1;1

A 3p orbital has: ? spherical node and ? planar node

1;1

a

An antibonding orbital forms when two orbital overlap ?, meaning the lobes that overlap have ? phases

out of phase; opposite

opposite phase→

antibonding

same phase→

bonding

c

b

b

Draw the structure but just put “a” to see the correct structure

a

you cannot tell without the free electrons

What is the formal charge on the oxygen atom?

0

you cannot determine without the free electrons

What are the formal charges on these atoms?

+1;+1;-2

carbon

How many free electrons are there on the central atoms shown?

6;2

How many free electrons are there on the central atoms shown?

2;4;0

Draw Lewis formulas of H3PO4, H3PO3 and H3PO2

a

type “a“

a

Draw the shape of a 4p atomic orbital. A 4p atomic orbital has ? lobes: ? planar and ? spherical.

three; one; two

A 3p orbital has:

a) One spherical node and one planar node

b) One spherical node and two planar nodes

c) Two spherical nodes and one planar node

d) Two spherical nodes and two planar nodes

a

Draw a structure of propane, C₃H₈. (type “a“)

a

Draw a structure of propene, C3H6 (hint: propene contains a double bond). (type “a“)

a

Draw a structure of propyne, C3H4 (hint: propyne contains a triple bond). (type “a“)

a

Which of the following compounds has the smallest H-Y-H bond angle?

a) CH4

b) H2O

c) NH3

d) CH3CH3

b

1 Å =

1 X 10^-10 m

A carbon-carbon bond has the length of:

1.54Å

The shape tetrahedral has a H-Y-H bond angle of:

109.5

The shape trigonal pyramidal has a H-Y-H bond angle of:

107.3

The shape bent has a H-Y-H bond angle of:

104.5

from right to left (sp, sp2, or sp3)

sp;sp;sp3;sp3;(c)sp2;(o)sp2; sp3;sp3

Draw it out and type “a“

a

a triple carbon bond has the lenght of:

1.20 Å

a hydrogen carbon bond has the lenght of:

1.06 Å

sp³ carbon = ?°
sp² carbon = ?°
sp carbon = ?°

109.5; 120; 180

draw and type “a“

a

H:0,B:-1.N:+1. This molecule has the same amount of valence electrons as a molecule of ethane, so it is isoelectronic with ethane

Only one of the names provided below is a correct IUPAC name. Which one is it?

a) 2-ethylbutane

b) 3-ethyl-2-methylhexane

c) 2-isopropylpentane

d) 3,3-dipropylpentane

b

Cyclobutane has the following type(s) of strain:

a) steric and angle

b) torsional

c) torsional and steric

d) torsional and angle

d

Cyclohexane has what type of strain? In chair? In boat?

strain-free; torsional and steric

Cyclopentane has what type of strain in envelope confirmation and half chair?

torsional and angle

Cyclopropane has what type of strain?

angle and torsional

sp2

a

Boiling points of various classes of organic compounds increase in the following order:

alkanes < ethers < amines < alcohols

Boiling points of amines increase in the following order:

tertiary amine < secondary amine < primary amine

Name Intermolecular Interactions in order of DECREASING strength, so start with the strongest

ion-ion > ion-dipole > hydrogen bond > dipole-dipole > dipole-induced dipole > London interactions

b,a,d,c

a

the formulas are incomplete

a

a

c

Connectivity; (CH3)3COH

1-cyclopropyl-2,5-diethyl-3.4-dipropylcylopentane

b

d

b

c

What is the name of this molecule

phenol

What is the name of this molecule

cyclopentyl alcohol

What is the name of this molecule

aniline

What is the name of this substituent?

propyl

What is the name of this substituent?

butyl

What is the name of this substituent?

isopropyl

What is the name of this substituent?

isobutyl

What is the name of this substituent?

s-butyl

What is the name of this substituent?

t-butyl

What is the name of this substituent?

neopentyl

What is the name of this substituent?

isohexyl

Classify each of the following compounds as ionic or covalent. If one of the bonds in a molecule is ionic, the compound is classified as ionic. Only if all the bonds are covalent, the compound is considered to be covalent.

LiH ; NaF ; SO2 ; CH3Li ; MgCl2

covalent; ionic; covalent; covalent; ionic

the nitrogen on the right

a

a

+1;+1;-1

Identify the hybridization of each of the C, N and O atoms in the following structure

a

How many electrons are there on the central atoms shown below?

2;4;2

Identify the hybridization of each of the C, N and O atoms in the following structure

a

Calculate the formal charge on the central atom in the molecule below. The formulas below are complete Lewis formulas

+2;+1;-1

Why is the formula shown below not a correct Lewis structure of nitric acid? Draw an acceptable Lewis structure of nitric acid.

A nitrogen atom cannot make five bonds