Gre Chemistry – Flashcards

in bicyclic systems indicates that the subsituent on a bridge is on the side of the smaller bridge

substituent on large bridge of bicyclic systems

alkenes -> alcohols/aldehydes/acids
alcohol-from sodium borohydride
aldehydes-from zn, pph3, dimethyl sulfide
acids-peroxides

substances that attract water easily and make it hard to use at standards
ex. KOH, NaOH

generally used to study the electrochemical properties of an analyte in solution.
-marked by a cycle of potential

The increase in the internal energy of a system is equal to the amount of energy added by heating the system, minus the amount lost as a result of the work done by the system on its surroundings.

E(universe) doesn’t change

during an electronic transition, a change from one vibrational energy level to another will be more likely to happen if the two vibrational wave functions overlap more significantly.

averaging scans improves by a squaree root

–O(–)
–OH
–OR
–OC6H5
–OCOCH3
-NH2
–NR2
–NHCOCH3
–R
–C6H5

–NO2
–NR3(+)
–PR3(+)
–SR2(+)
–SO3H
–SO2R –CO2H
–CO2R
–CONH2
–CHO
–COR
–CN

–F
–Cl
–Br
–I
–CH2Cl
–CH=CHNO2

prone to decarboxylation following hydrolysis

if the two substituents are on the same carbon

two substituents on adjacent carbon atoms

attached to the carbon atom of a double bond

any of a class of minerals of general formulation A2+B3+2O2-4 which crystallise in the cubic (isometric) crystal system, with the oxide anions arranged in a cubic close-packed lattice and the cations A and B occupying some or all of the octahedral and tetrahedral sites in the lattice. A and B can be divalent, trivalent, or quadrivalent cations, including magnesium, zinc, iron, manganese, aluminium, chromium, titanium, and silicon. Although the anion is normally oxide, structures are also known for the rest of the chalcogenides. A and B can also be the same metal under different charges, such as the case in Fe3O4 (as Fe2+Fe3+2O2-4).

pinel – MgAl2O4, after which this class of minerals is named

given by 1/2(c1z1^2 + c2z2^2 etc)

where c is the concentration of the species and z is the charge

a subclass of voltammetry where the working electrode is a dropping mercury electrode (DME), useful for its wide cathodic range and renewable surface

is a device for measuring the magnetic susceptibility of metals or metal complexes.

not for d3, d10 and d8 but for everything else if octahedral

describes an acid as an oxide ion acceptor and a base as an oxide ion donor. For example:
MgO (base) + CO2 (acid) → MgCO3

‘Hard’ applies to species that are small, have high charge states, and are weakly polarizable. ‘Soft’ applies to species that are large, have low charge states and are strongly polarizable. Acids and bases interact, and the most stable interactions are hard-hard and soft-soft. This theory has found use in organic and inorganic chemistry

attack at aromatic carbon with good leaving group vs. attack at unsbustituted carbon

In computational physics and chemistry, the Hartree–Fock (HF) method is an approximate method for the determination of the ground-state wave function and ground-state energy of a quantum many-body system

states that in closed-shell Hartree-Fock theory, the first ionization energy of a molecular system is equal to the negative of the orbital energy of the highest occupied molecular orbital (HOMO).

E No symmetry, chiral CFClBrH, lysergic acid

E σh Planar, no other symmetry thionyl chloride, hypochlorous acid

E i Inversion center anti-1,2-dichloro-1,2-dibromoethane

E 2C∞ σv
linear hydrogen chloride, dicarbon monoxide

E 2C∞ ∞σi i 2S∞ ∞C2 linear with inversion center dihydrogen, azide anion, carbon dioxide

E C2 “open book geometry,” chiral hydrogen peroxide

E C3 propeller, chiral triphenylphosphine

E C2 i σh Planar with inversion center trans-1,2-dichloroethylene

E 2C4 C2 2σv 2σd square pyramidal xenon oxytetrafluoride

E C3(z) 3C2 triple helix, chiral Tris(ethylenediamine)cobalt(III) cation

E C2(z) C2(y) C2(x) i σ(xy) σ(xz) σ(yz) planar with inversion center ethylene, dinitrogen tetroxide, diborane

E 2C3 3C2 σh 2S3 3σv trigonal planar or trigonal bipyramidal boron trifluoride, phosphorus pentachloride

E 2C4 C2 2C2′ 2C2 i 2S4 σh 2σv 2σd square planar xenon tetrafluoride

E 2C5 2C52 5C2 σh 2S5 2S53 5σv pentagonal ruthenocene, eclipsed ferrocene, C70 fullerene

E 2C6 2C3 C2 3C2′ 3C2 i 3S3 2S63 σh 3σd 3σv hexagonal benzene, bis(benzene)chromium

E 2S4 C2 2Ch 2C2′ 2σd 90° twist allene, tetrasulfur tetranitride

E 2S4 C2 2Ch 2C2′ 2σd 90° twist allene, tetrasulfur tetranitride

E 2C3 3C2 i 2S6 3σd 60° twist ethane (staggered rotamer), cyclohexane (chair conformer)

E 2S8 2C4 2S83 C2 4C2′ 4σd 45° twist dimanganese decacarbonyl (staggered rotamer)

E 2C5 2C52 5C2 i 3S103 2S10 5σd 36° twist ferrocene (staggered rotamer)

E 8C3 3C2 6S4 6σd tetrahedral methane, phosphorus pentoxide, adamantane

E 8C3 6C2 6C4 3C2 i 6S4 8S6 3σh 6σd octahedral or cubic cubane, sulfur hexafluoride

The haloform reaction is a chemical reaction where a haloform (CHX3, where X is a halogen) is produced by the exhaustive halogenation of a methyl ketone (a molecule containing the R-CO-CH3 group) in the presence of a base.[1] R may be H, alkyl or aryl. The reaction can be used to produce CHCl3, CHBr3 or CHI3.
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addition/formation of an amine group

addition of a new carbon fragment via carbon-carbon bond formation

a carbonyl with an R group is added to a molecule

has the form
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where
S is the total spin quantum number. 2S+1 is the spin multiplicity: the maximum number of different possible states of J for a given (L,S) combination.
L is the total orbital quantum number in spectroscopic notation. The symbols for L = 0,1,2,3,4,5 are S,P,D,F,G,H respectively.
J is the total angular momentum quantum number.

when three ligands share the same face of an octahedron

Positron emission is a type of beta decay, sometimes referred to as “beta plus” (β+). In beta plus decay, a proton is converted, via the weak force, to a neutron, a positron (also known as the “beta plus particle”, the antimatter counterpart of an electron), and a neutrino.

625–740 nm

440–490 nm

determined by observed optical rotation (alpha) divided by the path length (dm) and concentration in (g/mL)

intramolecular claisen condensation (makes a beta keto ester from two esters under basic conditions)

a carbon-carbon bond forming reaction that occurs between two esters or one ester and another carbonyl compound in the presence of a strong base, resulting in a β-keto

powerful carbon-carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl.

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“rock-salt”
NaCl, AgCl, AgBr, KBR, LiCl, RbI, Tio, MgO, CaO

-cubic array of anions with cations occupying all of the octahedral holes.

While the halite structure is almost always drawn to illustrate its cubic nature, recall from the previous discussion that the face-centered cubic array can be alternately viewed as a series of ABC-stacked hexagonal layers.

“sphalerite” structure

ZnS, CdS, HgS, CuCl

Cubic array of Zn2+ with S2- in half of the tetrahedral holes

CaF2, BaCl2, PbO2, HgF2 etc.

Cubic array of Ca2+ ions with F- in all the Tetrahedral holes

switch anion and cation to have a curbic array of anions with cations occupying the tetrahedral holes

K2O, K2S, Li2O, Na2O etc.

ZnS, ZnO, MnS, beO

hexagonal array of Zn2+ with S2- occupying half of the tetrahedral holes

NiAs, NiS, CoS, FeS

Hexagonal array of As3- ions with Ni3+ occupying all the octahedral holes

TiO2, MnO2, MgF2, SnO2, NiF2

Hexagonal Array of O2- with Ti4+ occupying half of the octahedral holes

a means of calculating the lattice energy of a crystalline ionic compound. In 1918[1] Max Born and Alfred Lande proposed that the lattice energy could be derived from the electrostatic potential of the ionic lattice and a repulsive potential energy term.[2]

[image] (Joules/mol)

where

[image] = Avogadros number
[image] = Madelung constant, relating to the geometry of the crystal.
[image] = charge of cation in electron units
[image] = charge of anion in electron units
[image] = electron charge in coulombs, 1.6022 ? 10−19 C

[image] = permittivity of free space

[image] = 1.112 ? 10−10 C?/(J m)
[image] = distance to closest ion in meters
[image] = Born exponent, a number between 5 and 12, determined experimentally by measuring the compressibility of the solid, or derived theoretically.

Takes into account the repulsive components of the ionic solid that the Born Lande may not

HCl-hydrochloric acid

HBr-Hydrobromic Acid

HI-Hydroiodic Acid

HNO3-Nitric Acid

H2SO4-Sulfuric Acid

HClO4-Perchloric Acid

The sum is equal to 14 at 25 degrees celsius

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and

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A vacancy, a point defect in which an atom or ion is missing from its usual site. Doesn’t change overall stoichiometry and is determined by density measurements

A point defect in which an atom has been displaced to an intersittial site in the lattice. More common in open structures where the coordination numbers are low

image

The Total Energy of a System and its surroundings is always constant

U=Q-W

H = U + PV

for constant pressure (atmospheric conditions)

ΔH = ΔU + PΔV

Cv = (dU/dT)

Cp=(dH/dT)

Cp-Cv = R

The Entropy of the universe tends to increase

The entropy of all perfect crystalline substances is the same at absolute zero

the volume of a given mass of gas is directly proportional to its temperature, if the pressure remains constant

the volume of a given mass of gas varies inversely with the pressure (constant temperature)

Текст ответа

G = H-TS (usually constant pressure)

A = U – TS (usually constant volume

F=C-P+2

F = degrees of freedom

C=components

P=phases

the vapor pressure of an ideal solution is dependent on the vapor pressure of each chemical component and the mole fraction of the component present in the solution.

Once the components in the solution have reached equilibrium, the total vapor pressure p of the solution is:

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and the individual vapor pressure for each component is

[image]

where

p*i is the vapor pressure of the pure component
xi is the mole fraction of the component in solution

[image]

or

[image]

where:

ΔP is the pressure drop
L is the length of pipe
μ is the dynamic viscosity
Q is the volumetric flow rate
r is the radius
d is the diameter

d[A]/dt = -k [A]

[A] = [A]0 exp(-k t)

ln([A]) = ln([A]0) – k t

d[A]/dt = -k [A]2 or dx/dt = -k [A][B]

1/[A] – 1/[A]0 = k t  or
(1/(a-b)) [ln((a-x)/(b-x))-ln(a/b)] = k t  

1/[A] = 1/[A]0 + k t

Splitting of energy levels between which the transition occurs in the presence of a magnetic field

 the shifting and splitting of spectral lines of atoms and molecules due to the presence of an external static electric field

Salts containing Group I elements are soluble (Li+, Na+, K+, Cs+, Rb+). Exceptions to this rule are rare. Salts containing the ammonium ion (NH4+) are also soluble.

Salts containing nitrate ion (NO3-) are generally soluble.

Salts containing Cl -, Br -, I – are generally soluble. Important exceptions to this rule are halide salts of Ag+, Pb2+, and (Hg2)2+. Thus, AgCl, PbBr2, and Hg2Cl2 are all insoluble

Most silver salts are insoluble. AgNO3 and Ag(C2H3O2) are common soluble salts of silver; virtually anything else is insoluble

Most sulfate salts are soluble. Important exceptions to this rule include BaSO4, PbSO4, Ag2SO4 and SrSO4

hydroxide salts are only slightly soluble. Hydroxide salts of Group I elements are soluble. Hydroxide salts of Group II elements (Ca, Sr, and Ba) are slightly soluble. Hydroxide salts of transition metals and Al3+ are insoluble. Thus, Fe(OH)3, Al(OH)3, Co(OH)2 are not soluble

Most sulfides of transition metals are highly insoluble. Thus, CdS, FeS, ZnS, Ag2S are all insoluble. Arsenic, antimony, bismuth, and lead sulfides are also insoluble

Carbonates are frequently insoluble. Group II carbonates (Ca, Sr, and Ba) are insoluble. Some other insoluble carbonates include FeCO3 and PbCO3.

Chromates are frequently insoluble. Examples: PbCrO4, BaCrO4 

Phosphates are frequently insoluble. Examples: Ca3(PO4)2, Ag3PO4

1) minimize Q (solute concentration) by adding slowly

2) maximize S (precipitate solubility) by doing at higher temperature

At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

FOR DILUTE SOLUTIONS!!

Potentiometry-measure EMF compared to standard zero current. either uses electrodes (like pH meters) to directly measure ion activity, or uses electrodes to find end points of titrations

Voltammetry-electrolysis is carreid out so the analyte is completely oxidized/reduced to a product of known composition. requires application of current through the whole process

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Baeyer strain theory or strain theory explains specific behaviour of chemical compounds in terms of bond angle strain.
It was proposed by Adolf von Baeyer in 1885 to account for the unusual chemical reactivity in ring opening reactions of cyclopropanes and cyclobutanes where this angle strain is relieved.

Any strain resulting from torsion is also called Pitzer Strain or eclipsing strain

The Mohr method uses chromate ions as an indicator in the titration of chloride ions with a
silver nitrate standard solution. After all the chloride has been precipitated as white silver
chloride, the first excess of titrant results in the formation of a silver chromate precipitate,
which signals the end point

The Kjeldahl method in analytical chemistry is a method for the quantitative determination of nitrogen in chemical substances developed by Johan Kjeldahl in 1883.

The Kjeldahl method’s universality, precision and reproducibility have made it the internationally-recognized method for estimating the protein content in foods and it is the standard method against which all other methods are judged. It does not, however, give a measure of true protein content, as it measures non-protein nitrogen in addition to the nitrogen in proteins.

[image]

Standardizes a silver nitrate solution using potassium chloride as a primary standard

titration of Cyanide with silver ion

Standardizing of Potassium Permanganate Solution

s a special type of epimer. It is a stereoisomer (diastereomer, more exactly) of a cyclic saccharide that differs only in its configuration at the hemiacetal (or hemiketal) carbon, also called the anomeric carbon

[image]

Π = iMRT

n’ = 2

n’ = 3

n’ = 1

11.5

9.5

5.5

7-8

5.5-8.5

3.5-4.5

0.5-5.5

1.5-2.5

3300 – 3600 Strong and Broad

2500 – 3000 Very Broad

3200-3500 (sometimes doublet of NH2)

3300

3000-3100

2800-3000

2250-2300

2100

1680-1820

1600

1050-1150

No protic acids in HF solvent

Can occur in acid and base, but not oxidizing conditions

The Cope rearrangement is an extensively studied organic reaction involving the [3,3]-sigmatropic rearrangement of 1,5-dienes. It was developed byArthur C. Cope. For example 3-methyl-1,5-hexadiene heated to 300°C yields 1,5-heptadiene.

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The McLafferty rearrangement is a reaction observed in mass spectrometry. It is sometimes found that a molecule containing a keto-group undergoes β-cleavage, with the gain of the γ-hydrogen atom. This rearrangement may take place by a radical or ionic mechanism

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The Hofmann rearrangement is the organic reaction of a primary amide to a primary amine with one fewer carbon atom

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Hofmann elimination (also known as exhaustive methylation) is a process where an amine is reacted to create a tertiary amine and an alkene by treatment with excess methyl iodide followed by treatment with silver oxide, water, and heat [image]

Test for aldehydes

Temperature 

T(Rankine) = T(F) + 460

The Van Deemter equation in chromatography relates the variance per unit length of a separation column to the linear mobile phase velocity by considering physical, kinetic, and thermodynamic properties of a separation.[1] These properties include pathways within the column, diffusion (axial and longitudinal), and mass transfer kinetics between stationary and mobile phases.

[image]

Where

A = Eddy-diffusion
B = Longitudinal diffusion
C = mass transfer kinetics of the analyte between mobile and stationary phase
u = Linear Velocity.

he existence of co-ordination compounds that have the same composition differing with the connectivity of the metal to a ligand.

Electronic: can’t do s-s p-p d-d etc. 

Rotational-must differ by +-1

Need a net dipole moment

an unsaturated compound derived by the reaction of an aldehyde or ketone with a secondary amine followed by loss of H2O

[image]

is a functional group or chemical compound containing a carbon–nitrogen double bond [1]. Due to their diverse reactivity, imines are common substrates in a wide variety of transformations. An imine can be synthesised by the nucleophilic addition of an amine to a ketone or aldehyde giving a hemiaminal -C(OH)(NHR)- followed by an elimination of water to yield the imine

[image]

Rotational and Vibrational

For the spontaneous Raman effect, the molecule will be excited from the ground state to a virtual energy state, and relax into a vibrational excited state. Two series of lines exist around this central vibrational transition. They correspond to the complimentary rotational transition. Anti-Stokes lines correspond to rotational relaxation whereas Stokes lines correspond to rotational excitation.

higher number, more deshielded