Unit 1 Introduction to Organic Chemistry Flashcards

1
Q

Origin of Organic Chemistry

A
  • Foundations date from mid-1700’s
  • Compounds obtain from plants and animals
  • Low-melting solids
  • Hard to isolate, purify, and work with
  • considered to have some vital force as they were from living sources
  • though that could not be synthesized in lab
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2
Q

In 1816 he found out that soap can e separated into several organic compounds which he termed fatty acids

A

Chevreul

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3
Q

In 1828 he showed that it was possible to convert organic salt ammonium cyanate into organic substance urea

A

Wohler

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4
Q

the study of carbon compounds, more than 50M known chemical compounds contain carbon

A

organic chemistry

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5
Q

It is a group 4A element that can share 4 valence electrons and form 4 covalent bonds.
Able to bond with one another to form long chains and rings.
The only element that has the ability to form immense diversity of compounds

A

Carbon

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6
Q

Bonding is almost covalent
May be gases, liquids, or solid with low melting points (less than 360’C)
Most are insoluble in water
Most are soluble in organic solvents such as diethyl ether, toluene, and dichloromethane
Aqueous solutions do not conduct electricity
Almost all burn
Reactions are usually slow

A

Organic Compound

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7
Q
Most have ionic bonds
Most are solids with high melting points
Many are soluble in water
Almost all are insoluble in organic solvents 
Aqueous solutions conduct electricity
Very few burn
Reactions are often fast
A

Inorganic Compounds

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8
Q

consist of Nucleus = proton+ neutron (contains essentially all the mass of the atom) and Electron

A

Atom

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9
Q

diameter of an atom

A

2x10-10m or 200 picometers

Angstrom is 10-10m =100 pm

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10
Q

number of protons or electrons in an atom’s nucleus

A

atomic number (Z)

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11
Q

number of protons plus neutrons

A

mass number (A)

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12
Q

weighted average mass in atomic mass units (amu) of an element’s naturally occurring isotope

A

atomic mass or atomic weigt

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13
Q

atoms with the same atomic number but different mass numbers

A

Isotopes

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14
Q

mathematical equation that describes the behavior of a specific electron in an atom

A

wave equation

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15
Q

the solution of wave equation denoted by Greek letter psi

A

wave function or orbital

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16
Q

4 kinds of orbitals:

A

s orbitals -spherical, nucleus at the center
p orbitals -dumbbell-shaped, nucleus at the middle (px, py, or pz)
d orbitals -elongated dumbbell-shaped, nucleus at the center
f orbitals

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17
Q

atomic structue - orbitals:

A

orbitals of an atom are organized into different electron shells
centered around the nucleus in shells of increasing size and energy
different shells contain different numbers and kinds ff orbitals
each orbital can be occupied by 2 electrons

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18
Q

atomic structure: electron configuration:

A

ground-state electron configuration: listing of orbitals occupied by an atom’s electrons
called lowest-energy arrangement

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19
Q

lowest energy orbitals fill first in order of 1s-2s-2p-3s-3p-4s-3d

A

Aufbau principle

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20
Q

electrons act as if they were spinning around an axis
spin can have only 2 orientations up and down
only 2 electrons can occupy an orbital, and they must be of opposite spin

A

Pauli exclusion principle

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21
Q

if two or more empty orbitals of equal energy are available, electrons occupy each with parallel spins until all orbitals have one electron

A

Hund’s rule

22
Q

in 1858 they independently proposed that, in all organic compounds, carbon is tetravalent- they always form four bonds when it joins other elements

A

August Kekule an Archibald Couper

23
Q

in 1874 they proposed that four bonds of Carbon are not oriented randomly but have specific directions

A

Jacobus van’t Hoff and Joseph Le Bel

24
Q

atoms form _____ because the resulting compound is more stable than separate atoms

A

bonds

25
Q

atom’s outermost shell

A

valence shell

26
Q

ions held together by a electrostatic attraction formed as a result of electron transfers

A

Ionic bonds

27
Q

formed by sharing of electrons e.g CH4, methane

A

Covalent bond

28
Q

electron-dot structures that represents valence shell electrons of an atom as dots

A

Lewis structure

29
Q

line-bond structures that indicates two-electron covalent bond as a line drawn between atoms

A

Kekule structures

30
Q

has five valence electrons (2s2 2p3) forming three bonds

A

Nitrogen

31
Q

valence electron not use in bonding

A

Lone pair

32
Q

a covalent bond forms when 2 atoms approach each other closely and singly occupied orbital on one atom overlap a singly occupied orbital on the other atom
H-H bond results from the overlap of 2 singly occupied hydrogen 1s orbitals
H-H bond is cylindrically symmetrical, sigma (0) bond

A

Valence bond theory

33
Q

ideal distance between nuclei that leads to maximum stability
too close= they repel
too far= bonding is weak

A

bond length

34
Q

occurs when atoms are ready to form bonds

to predict the bond angles in these molecules we use the Valence-Shell Electron-Pair (VSPER) Model

A

Hybridization

35
Q

the angle between two atoms bonded to a central form

A

bond angle

36
Q

3 hybrid orbitals:

A

sp3
sp2
sp

37
Q
he proposed the s orbital and three p orbitals an combine, or hybridize, to form four equivalent atomic orbitals with tetrahedral orientation
109.5 degree angle
Single Bond
e.g methane CH4
bond angle form between 2 adjacent bonds
A

Linus Pauling

38
Q

the simplest molecule containing carbon-carbon bond

A

Ethane C2H6

39
Q

___orbitals are in a plane with an angle of 120 degrees from each other
exhibits double bond
trigonal planar geometry
head-on overlap gives what is called a sigma (0) bond
sideways overlap gives a pi bond

A

sp2

40
Q

H atoms forms s bonds with four sp2 orbitals
H-C-H and H-C-C form bond angles of about 120 degrees
C-C bond in ethylene is shorter and stronger than single bond in ethane

A

Ethylene C2H4

41
Q

____ can form a triple bond sharing six electrons
Carbon 2s orbital hybridizes with a single p orbital giving 2 sp hybrids sp orbitals are linear geometry, 180 degrees apart on axis

A

Carbon

42
Q

sharing of six electrons form C-C triple bond
2 sp orbitals from s bonds with hydrogens
shortest and strongest carbon-carbon bond

A

Acetylene C2H2

43
Q

when it is bound to 2 other atoms with the help of 2 double bonds ore one single and one triple bond. Molecules have linear arrangement of the atoms with a bond angle of 180 degree

A

sp Hybridization

44
Q

bonding takes place between 1 s-orbital with 2 p orbitals. Formation of 2 single bonds and one double bond between three atoms. The hybrid orbitals are placed in a triangular arrangement with 120 degree angle between bonds

A

sp2 Hybridization

45
Q

molecular orbital that is lower in energy than the atomic orbitals from which it is formed

A

Bonding MO

46
Q

molecular orbital that is higher in energy than the atomic orbitals from which it is formed

A

Antibonding MO

47
Q

bonds that are neither fully ionic nor fully covalent but are somewhere between the two extremes

A

polar covalent bonds

48
Q

intrinsic ability of an atom to attract shared electrons in a covalent bond

A

electronegativity

49
Q

molecule structures that cannot be shown with a single representation
such structure are delocalized are are represented by_____

A

resonance form

50
Q

structure with resonance forms, that does not alternate between the forms e.g Benzene
resonance leads to stability

A

resonance hybrids

51
Q

_______is sstabel because it is symmetrical

A

Allylic Carbocations