Unit 1 Introduction to Organic Chemistry Flashcards

(51 cards)

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

25
atom's outermost shell
valence shell
26
ions held together by a electrostatic attraction formed as a result of electron transfers
Ionic bonds
27
formed by sharing of electrons e.g CH4, methane
Covalent bond
28
electron-dot structures that represents valence shell electrons of an atom as dots
Lewis structure
29
line-bond structures that indicates two-electron covalent bond as a line drawn between atoms
Kekule structures
30
has five valence electrons (2s2 2p3) forming three bonds
Nitrogen
31
valence electron not use in bonding
Lone pair
32
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
Valence bond theory
33
ideal distance between nuclei that leads to maximum stability too close= they repel too far= bonding is weak
bond length
34
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
Hybridization
35
the angle between two atoms bonded to a central form
bond angle
36
3 hybrid orbitals:
sp3 sp2 sp
37
``` 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 ```
Linus Pauling
38
the simplest molecule containing carbon-carbon bond
Ethane C2H6
39
___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
sp2
40
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
Ethylene C2H4
41
____ 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
Carbon
42
sharing of six electrons form C-C triple bond 2 sp orbitals from s bonds with hydrogens shortest and strongest carbon-carbon bond
Acetylene C2H2
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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
sp Hybridization
44
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
sp2 Hybridization
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molecular orbital that is lower in energy than the atomic orbitals from which it is formed
Bonding MO
46
molecular orbital that is higher in energy than the atomic orbitals from which it is formed
Antibonding MO
47
bonds that are neither fully ionic nor fully covalent but are somewhere between the two extremes
polar covalent bonds
48
intrinsic ability of an atom to attract shared electrons in a covalent bond
electronegativity
49
molecule structures that cannot be shown with a single representation such structure are delocalized are are represented by_____
resonance form
50
structure with resonance forms, that does not alternate between the forms e.g Benzene resonance leads to stability
resonance hybrids
51
_______is sstabel because it is symmetrical
Allylic Carbocations