ORGO Chapter 2-3
Which of these is the weakest of the intermolecular attractive forces? A) Ion-ion B) van der Waals C) Dipole-dipole D) Covalent bonding E) Hydrogen bonding
B
benzene
Consists of a ring of six carbon atoms with alternating single and double carbon-carbon bonds. c6h6 primary aromatic hydrocarbon
any diatomic molecules in which the two atoms are DIFFERENT (nd thus have differing EN) WILLL HAVE A
DIPOLE MOMENT
Deprotonation of Carboxylic Acids
Deprotonation of this functional group gives a resonance-stabilized anion in which the negative charge is spread over two oxygen atoms.
leveling effect
If a base stronger than HO- is dissolved in water, the base reacts with water to produce hydroxide. This is called the leveling effect. The inability of a solvent to distinguish the strength of an acid (or base) that is stronger than the conjugate acid (or conjugate base) of the solvent If a base stronger than HO- is dissolved in water, the base reacts with water to produce hydroxide. This is called the leveling effect.
guidelines for water solubility: for compounds containing one hydrophilic group ( and thus able to form strong hydrogen bonds), the follow approximate guidelines hold:
- compounds w/ 1-3 carbon atoms are water soluble -componds with 4-5 carbons are borderline soluble - compounds with six carbons + are insolubl
cyclic nitriles are named by adding the suffix -_______
-carbonitrile
pka
-logKa
ph =
-log[H3O+]
carboxylic acids (like acetic acid) usually have a pka of
3-5
carboxylic acids general pka
3-5
A non-zero dipole moment is exhibited by: A) SO2 B) CO2 C) CCl4 D) BF3
A
The solid alkane CH3(CH2)18CH3 is expected to exhibit the greatest solubility in which of the following solvents? A) CCl4 B) CH3OH C) H2O D) CH3NH2 E) HOCH2CH2OH
A
kekule structure
A classical structural formula for an aromatic compound, showing localized double bonds. structure resembling benzene's c6h6 structure. there is much evidence that proves this structure as incorrect if benzene had alternating single and double bonds as the Kekule structure indicates, we would expect the lengths of the carbon-carbon bonds around the ring to be alternately longer and shorter in fact, the c-c bonds of benzene are all the same lengths (a value in between that of a c-c single bond and a c=c double bond solution: resonance structures
ACID STRENGTH IS CHARACHTERIZED IN TERMS OF
ACIDITY CONSTANT (Ka) or pKa values
acetylene vs ethylene which one is more acidic
Acetylene (H-C≡C-H) is more acidic. The conjugate base of acetylene has a negative charge associated with a lone pair in an sp hybridized orbital, which is more stable than a negative charge associated with a lone pair in an sp2 hybridized orbital.
baking powder
It is a powder mixture that contains both sodium bicarbonate and an acid salt, such as potassium bitartrate: a mixture of sodium bicarbonate and cream of tartar, used instead of yeast in baking
strong bases
LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
sodium bicarbonate
NaHCO3
A molecule with a dipole moment is a
POLAR MOLECULE
ethers
R-O-R or may be R-O-R' where R' may be a phenyl or alkyl group
alcohols
R-OH
amides
RCONH2, RCONHR', RCONRR'
bp of h20, HF, and NH3
REPECTIVELY, 100, 19.5, -33.4
endergonic reaction
Reaction that absorbs free energy from its surroundings. non spontaneous
solvent effects are invoked to explain small differences in pKa values . EXPLAIN THE SOLVATING EFFECT
Small pka can be explained by the solvating effect. some ions can be seen as sterically hindered (bulky) and is thus less capable of interacting with the solvent which makes it less stable.
is h2o of h2s more acidic
Sulfur and oxygen are in the same column of the periodic table (group 6A), so we must compare their size. Sulfur is larger than oxygen and can better stabilize the negative charge that will be generated upon deprotonation. Therefore, H2S is expected to be more acidic than H2O.
THE LARGER THE ATOM,
THe better it is to stabilize a negative charge (by spreading the charge over a larger volume)
which one is more acidic: ethanol or water
The CH3CH2 group in ethanol provides a small amount of steric bulk that is absent in water. As such, water is more acidic than ethanol (for the same reason that ethanol is more acidic than tert-butanol). Indeed, the pKa of water (15.7) is slightly lower than the pKa of ethanol (16).
Deprotonation
The removal of a hydrogen cation (H+) from a molecule
AMIDE
Where a carbonyl group is bonded to a nitrogen atom bearing hydrogen and/or alkyl groups
methylene group
a CH2 group
positive entropy change
a change from a more ordered system to less ordered
carbonyl group
a chemical group consisting of a carbon atom linked by a double bond to an oxygen atom
alkenyl halide
a compound with a halogen atom bonded to an alkene carbon
carbonyl group
a group where a carbon atom is linked by a double bond to an oxygen atom; if the carbon atom in the group is at the end of the carbon skeleton, it is called an aldehyde. If the group within a carbon chain is called ketones
aryl halide
a halocarbon in which one or more halogens are attached to the carbon atoms of an aromatic ring such as a benzene ring
Alkynes
a hydrocarbon compound with a carbon-carbon triple bond.
dipole
a molecule that has two poles, or regions, with opposite charges
benzyl alcohol
a primary alcohol (hydroxyl group attached to a primary carbon)
geraniol
a primary alcohol (hydroxyl group attached to a primary carbon)
Bronsted-Lowry base
a substance that can accept a proton proton acceptor
acid base reactions always favor the formation of
a weaker acid and the weaker base why? because the outcome of an acid base rxn is determined by the position of an equilibrium
endothermic
absorb heat have positive change in H (enthalpy) atoms have smaller enthalpy as reactants
some drugs are ___ and some are ____
acids; bases
thymine hydrogen bonds with
adenine
isopropyl alcohol
aka 2-propanol a secondary alcohol
acidity of alkyne, alkenes, and alkanes
alkyne hydrogen (ex. ethyne c2h2) is weakly acidic alkene (ex. ethene c2h4) and alkane (ex. ethane c2h6) are not acidic at all pka 25,44,50 respectively
electrophiles
all lewis acids reagents that seek electrons carbon atoms that are electron poor because of bond polarity but do not consider themselves carbocations
conjugate of carboxylic acid
always resonance stabilized
proteins contain
amide groups
strong acid
an acid that ionizes completely in aqueous solution HCl, HI, HBr, H2SO4 (Sulfuric acid), HNO4 (Nitric acid), HCLO4 (Perchloric acid)
aromatic compound
an organic compound that contains the benzene ring structure and may have a pleasant or unpleasant odor and flavor
When butane is deprotonated,
anegative charge is generated on a carbon atom
proton acidity increases from left to right in a given row on the table due to increasing stability of the base. explain this
as you go from L to R, electronegativity increases. and as you go right, the more polarized the H bond will be to the element (and the most positive the proton becomes), therefore the easier and more readily the proton will be lost and thus the more acidic.
why does basicity increase as you go left on the table
as you go left, the less EN elements get and the less able the element is to accept the negative charge (but can accept proton).
heteroatoms
atoms like oxygen, nitrogen, and sulfur that form covalent bonds and have unshared electron pairs Atoms in an organic compound other than carbon and hydrogen
dipole-dipole forces
attractions between oppositely charged regions of polar molecules most organic molecules have a permanent dipole moment resulting from a nonuniform distribution of bonding electrons
When an acidic compound is present in the dough or batter,
baking soda can be protonated, causing liberation of CO2
an sp3 carbanion is the strongest ___
base in a series based on carbon hydridization and an sp carbanion (an alkynide) is the weakeast base
why does ethanol have a higher boiling point that dimethyl ether
because ethanol has a hydrogen atom covalently bonded to an oxygen atom, it can form strong hydrogen bonds to each other molecules or dimethyl ether, because they lack a hydrogen atom attached to an electronegative atom, cannot form strong hydrogen bonds to each other
acid base reactions always favor the formation of a weaker acid and the weaker base. why?
because the outcome of an acid base rxn is determined by the position of an equilibrium . and equlibrium always favors the formation of the most stable (lowest potential energy) species. the weaker acid and the weaker base are more stable (less PE) than the stronger acid and base
However, when acidic ingredients are absent, the baking soda cannot be protonated, and CO2 is not produced. In such a situation, we must add
both the base (baking soda) and some acid
ETHENE AND PROPENE
c2h4 and c3h6 are among the most important industrial chemical sproduced in the US
Ethyl Alcohol (ethanol) Formula
c2h6o
alkyne examples
capillin: an antifungal agent dactylyne: a marine natural product that is an inhibitor of pentobarbital metabolism ethinyl estradiol: synthetic (lab made) alkyne whose estrogen-like properties have found use in oral contraceptives --> birth control!!!
ester
carbonyl group bonded to an alkoxyl (-OR) HAVE GENERAL FORMULA: RCO2R'E
protonation of a c=o
catalyzes a number of reactions For catalytic purposes, it is sufficient to have only a small percentage of the C=O bonds protonated.
entropy changes have to do with
changes in the relative order of a system
potential energy =
chemical energy
a factor (in addition to polarity and hydrogen bonding that affects the melting point of many organic compounds is the
compactness and rigidity of their individual molecules
alkyl halides
compounds in which a halogen atom (fluorine, chlorine, bromine, or iodine) replaces a hydrogen atom of an alkane ex. CH3Cl or CH3CH2Br also called haloalkanes classified as being primary, secondary, or tertiary
all lewis acids are
electrophiles that can accept an electron pair from a lewis base
the reaction that occurs in an aqueous solution of acetic acid is in
equilibrium
fats and oils contain ____ groups
ester
compounds containing a C=O bond directly next to an OH are generally mildly acidic, because
ex. acetic acids carboxylic acids
example of carboxylic acids
formic acid, acetic acid, and benzoic acid
Smaller alkanes (methane ch4 and butane c4h10) are
gases under ambient condition
alkyl groups
groups of atoms that are formed when one hydrogen atom is removed from an alkane molecule
cytosine hydrogen bonds with
guanine
mechanism for the reaction of water with hydrogen chloride
h20 + HCl --> h3o+ + Cl- a water molecule uses one of the nonbonding electron pairs of its oxygen to form a bond to a proton of HCl. this bond forms because the negatively charged electrons of the oxygen are attracted to the positively charged proton. The bond between hydrogen and chlorine breaks, and the electron pair goes to the chlorine atom this leads to the formation of a hydronium ion and chloride ion
a group of ethanol molecules is much ____ to separate from each other than a group of dimethyl ether molecules.
harder
nitriles
have carbon triple bonded nitrogen group with an R group the carbon and nitrogen are sp hybridized
heterolysis
heteroloysis of a bond to carbon atom can lead to either of two ions: an ion with a positive charge on the carbon atom called a carbocation or an ion with anegatively charged carbon atom called carbanion
molecules that are symmetrical generally have abnormally ____ MPs
high
primary carbon atom
if the carbon atom that bears the halogen is directly attached to only one other carbon
covalent bonds and potential energy
in covalent bonds, the lowest potential energy state occurs when atoms are at their ideal internuclear distance (bond length)
a convenient way to represent the relative PEs of molecules is
in terms of their relative ENTHALPIES (heat contents), H
electronegativity (for comparing atoms _____) and size (for comparing atoms in the same column)
in the same row (RIGHT LEFT)
Why are some alcohols soluble in water?
in these cases, the alkyl groups of the alcohols are relatively small (ex. ch3 in methanol) and the molecules therefore resemble water more than they do alkane. because carbon atoms combine with OH- to form hydrogen bonds with water.
proton acidity increases from left to right in a given row on the table due to
increasing stability of the conjugate base
carbanions
ion with negatively charged carbon atom electron rich anions that have unshared electron pair lewis bases seek a proton or some other positive center to which they can donate their electron pair and thereby neutralize their negative charge
carbocations
ion with positive charge on carbon electron deficient they have only six electrons in their 6 electrons in their valence shells and because of this carbocations are lewis acids short lived and highly reactive react rapidly with lewis bases (with molecules or ions tha tcan donate the electron pair that they need to achieve a stable octet of electrons electrophiles (electron loving)-- seek electrons
weak acids
ionize only slightly in aqueous solution
ethene
is is a natural plant hormone. produced naturally by fruits and is involved in the ripening process of these fruits
acetone
ketone that is found in blood, urine, and breath when diabetes mellitus is out of control
strong base
large pka value
the more potential energy an object has, the ____ stable it is
less
why is the proton bond strength weaker as we move down the column
less orbital overlap of successively larger elements down a column
many compounds of group IIIA elements like Boron and Aluminum are
lewis acids because group IIIA atoms have only a sextet of electrons in their outer shell
your body makes esters from
long-chain carboxylic acids called fatty acids by combining them with glycerol
the electrons of larger atoms like Iodine are
loosely held and easily polarized
fluorine
low polarizability small dispersion forces
a substance that boils at 150C at 1atm pressure will boil at a ____ temp if the pressur is reduced to .01 torr
lower
the formation of chemical bond is always associated with
lowering of PE of the atoms
alkyl group examples
methyl, ethyl, propyl, isopropyl , butyl, etc.
carboxylic acid
mildly acidic because their conjugate bases are resonance stabilized
conjugate base
molecule or ION that forms when an acid loses a proton
the primary source of alkanes are
natural gas and petroleum
if collectively , stronger bonds are formed in the products than in reactants, then change in H is
negative (EXOTHERMIC) Thus a negative change in H will contibute to making change in G negative and will consequently favor formation of products
Do alkanes have functional groups?
no
intermolecular (van der waals Forces)
not as strong as the forces in between ions but they do account for the fact that even completelyy nonpolar molecules can exist in liquids and solids ex. Dipole-dipole forces, hydrogen bonds, dispersion forces
when a lewis base seeks a positive center other than a proton, especially that of a carbon atom, chemists call it a
nucleophile (meaning nucleus loving)
ionic bond
occurs between two atoms with very large EN differences EX. LiF Formed when one or more electrons are transferred from one atom to another
1e10^-18
one debye (or one D)
way to name ethers
one way is to name the two alkyl groups attched to the oxygen in alphabetical order and add the word ETHER. If the two alkyl groups are the same, we use di- (ex. dimethyl ether)
Map of Electrostatic Potential (MEP)
one way to visualize the distribution of charge in a molec. regions of an electron density surface that has more negative are colored red. these regions would attrac positively charged species regions in a MEP that are less negative are blue and will attract electrons from another molecule
amines
organic compounds with an amino group considered an organic derivative of ammonia
Methane
principle component of natural gas ch4 the simplest alkane one major component of the early atmosphere still found in earth's atmosphere but not in an appreciable amount major component of Jupiter, Saturn, Uranus, and Neptune atmosphere some organisms produce methan from hydrogen and carbon dioxide (METHANOGENS)
leavening agents
produce CO2 that will make a dough or batter fluffy. A substance that triggers a chemical reaction that makes a baked product grow larger, or rise.
Because sodium bicarbonate is mildly basic, it will react with an acid to
produce carbonic acid, which in turn degrades into CO2 and water:
in lewis acid base theory
proton donors are not the only acids. many other species are acids as well i.e Aluminium chloride reacts with ammonia in the same way that a proton donor does.
higher molecular weight alkanes are obtained largely by
refining petroleum
release of heat
results from a change from PE to KE
constitutional isomers
same molecular formula, different connectivity
same molecular formula =
same molecular weight
if the carbon atom that bears the hydroxyl group also has two other carbon atoms attached to it, this carbon is called a __________, and the alcohol is a _______
secondary carbon, secondary alcohol
glucose contains
several hydroxyl groups (-oh) and in one of its forms contains an aldehyde group
weak acid
small pka value
baking soda is the household name for
sodium bicarbonate.
CARBON WITH A TRIPLE BOND IS ___ HYBRIDIZED
sp
in nitrile, carbon and nitrogen are ____ hybridized
sp
carbon with a double bond is ____ hybridized
sp2
A pair of electrons in an sp-hybridized orbital is held closer to the nucleus than a pair of electrons in an ___ or _____ hybridized orbital. As a result, electrons residing in an ____ orbital are stabilized by being close to the nucleus.
sp2 - or sp3 -hybridized orbital. sp
carbon with a single bond is ___ hybridzied
sp3
alkyl group
specific groups of carbon and hydrogen atoms that are not part of the functional groups groups that would be obtained by removing a hydrogen from an alkane An alkane with a hydrogen atom removed, e.g. CH3, C2H5; alkyl groups are often shown as 'R'. alkane's "functional group"
FROM THE STANDPOINT OF Covalent bonds, the state of greatest PE is the
state of free atoms, the state in which atoms are not bonded to each other at all. this is true bc the formation of chemical bond is always associated with lowering of PE of the atoms
weak acid = ____ conjugate base
strong
hcl
strong acid acid that is present in solution is really h3o+ because of leveling effect
large Ka means
strong acid if Ka is greater than 10, the acid will be completely dissociated from water
fluoride ion
strong base (because HF is weak acid)
Bronsted-Lowry acid
substance that can donate a proton proton donor
boiling point
temp at which the vapor pressure of a liquid equals the pressure of the atmosphere above it The temperature at which a liquid changes to a gas pressure dependent and reported to occur at 1atm nonpolar compounds (IMFs weak) usually have lower bps because they require less energy to separate molecules to transition from L--> G HEAVIER molecules requires greater thermal energy in order to acquire veloities great enough to escape Liquid phase and because the surface area of larger molecules acan be much greater, Intermolecular dispersion attractions can be also greater, further making it more difficult to separate IMF (Explains why increasing alkanes have increasing BPs)
if the carbon atom that bears the hydroxyl group also has 3 other carbon atoms attached to it, this carbon is called a __________, and the alcohol is a _______
tertiary carbon, tertiary alcohol
phenyl group
the benzene molecule minus one hydrogen atom
alkyl halides are classified as being primary, secondary, or tertiary. this classification is based on
the carbon atom to which the halogen is directly attached
the functional group of an alkyne
the carbon to carbon triple bond
acetone and acetaldehyde are examples of molecules with permanent dipoles because
the carbonyl groups that they contain is highly polarized
FUNCTIONAL GROUPS
the components of organic molecules that are most commonly involved in chemical reactions Defined groups of atoms in a molec. that give rise to the function (reactivity or physical properties) of the molec. often contain atoms having diff EN values and unshared electron pairs
percent ionization
the concentration of ionized acid in a solution divided by the initial concentration of acid multiplied by 100%
In order to compare acids without the use of pKa values, we must look at
the conjugate base of each acid
a drug's ability to transition between environments (polar and nonpolar) is a direct result of
the drug's acid-base properties
the strength of a bronsted lowry acid depends on
the extent to which a proton can be separated from it and transferred to a base removing the proton involves breaking a bond to the proton and it involves making the conjugate base more electrically negative
measure of strength for acids
the extent to which an acid transfers proton to a base
measure of strength for acids
the extent to which an acid transfers proton to a base percent of ionization
the energy required to overcome lattice energies and intermolecular or interionic attractions comes from
the formation of new attractive forces between solute and solventw
functional group of alcohol
the hydroxyl group attached to the sp3 hybridized carbon
because water is highly polar and because water is capable of forming strong hydrogen bonds,
the ion-dipole forces of attraction are also larger. the energy supplies by the formation of these forces i great enough to overcome the lattice energy and interionic attractions of an ionic crystal
the length of the arrow of the dipole moment indicates
the magnitude of the dipole moment
conjugate acid
the molecule or ion that forms when a base accepts a proton
in the process of dissolving
the molecules or ions must be separated from each other (like melting)
leveling effect
the observation that strong acids all have the same strength in water and are completely converted into solutions of H3O+ ions; strong bases are likewise leveled in water and are completely converted into solutions of OH- ions
in the liquid or solid state, dipole-dipole attractions cause the molecules to orient themselves so that
the positive end of one molec is directed toward the negative end of another
ionization
the process of adding or removing electrons from an atom or molecule, which gives the atom or molecule a net charge
two important factors determine the magnitude of dispersion forces:
the relative surface area of the molecule involved (generally longer molecules have greater attractive forces between them) the relative polarizability (how easily the electrons respond to a changing electric field) of electrons of the atoms involved
for the ionization of an acid, the less positive or more negative the value of the change in H is,
the stronger the acid will be because the more negative the change in H is, the more favorable it will be to make products from reactants during equilibrium. And if ionization results in a favor in product creation, the acid will be considered strong
the larger the pka of the conjugate acid
the stronger the base
bronsted lowry acid base reactions involve
the transfer of protons
the larger the pka value
the weaker the acid
the stronger the acid
the weaker the conjugate base
because HI, HBr, and HCl are all strong acids,
their conjugate bases (I-, Br-, Cl-) are all weak bases
ALDEHYDES AND KETONES have a ______ arrrangement of groups around the carbonyl carbon atom
trigonal planar arrangement thus the carbon atom is sp2 hybridyzed
t or f alcohols and phenols are different
true phenols differ significantly from alcohols in terms of their acidity
dipole moment formula
u= c * d c=electrostatic charge (typically on the order of 10^-10) and d= distance (typically on the order of 10^-8 cm) thus u is on the order of 10^-18
polar covalent bond
unequal sharing of electrons strongly influence the physical props and reactivity of molecules (because they usually are a part of all functional groups)
explanation for why nonpolar groups like long alkane chains avoid aqueous environments
very complex answer but really it is because of the unfavorable entropy change (from state to disorder to order) . for a nonpolar hydrocarbon chain to be accommodated by water, the water molecules have to form a more order structure around the chain and with this, the entropy change is unfavorable
Acetic acid is the main constituent in ____ solutions
vinegar
By determining the more stable conjugate base,
we can identify the stronger acid For example, if we determine that A- is more stable than B-, then HA must be a stronger acid than HB. we can identify the stronger acid
ammonia is a _____ base
weak
small Ka means
weak acid
water is a ____ acid
weak; pka = 15.7
equilibirum will always favor formation of the ___ acid
weaker acid (higher pka value)
phenyl group
when a benzene ring is attached to some other group of atoms in a molecule the benzene molecule minus one hydrogen atom
covalent bonds
when electrons are shared equally between atoms ex. ETHANE, METHANE, ETC. OCCURS BETWEEN TWO ATOMS WITH SIMILAR EN Bonds created by sharing electrons with other atoms.
why are alkynes more acidic that alkenes and alkanes
with hybrid orbitals, having more s charachter means that the electrons of the anions will usually be lower in energy and the anion will be more stable. (electrons of 2s orbitals have lower energy than those of 2p orbitals because electrons in 2s orbitals are much closer to the nucleus). thus the sp orbitals of the c-h bonds of ethyne are 50% s charachter while those of sp2 orbitals of ethene have 33.3% s this means in effect that the sp carbon atoms of ethyne act as if they were more electronegative than the sp2 carbon atoms of ethene
alcohols may be viewed structurally in two ways:
1. as hydroxyl derivatives of alkanes or 2. as alkyl derivates of water
alcohols general pka
15-18
alcohols usually have a pka of
15-18
____ alkyl groups can be derived from propane
2; propyl and isopropyl propyl: removal of a hydrogen from one of the end carbon atoms isopropyl: removal of a hydrogen from the middle carbon atom
alcohols
Alcohols are compounds that possess an O-H group, Alcohols can function very much like water (either as weak acids or as weak bases).
phenol
An alcohol with an aromatic ring; has slightly more acidic hydroxyl hydrogen's than other alcohols ex. Thymol ( a phenol found in thyme) and Estradiol (a sex hormone that contains both alcohols and phenols)
benzyl group
Bn- or Ph-CH2-
is hBr or hCl a stronger acid
Bromine and chlorine are in the same column of the periodic table (group 7A), so we must compare their size. Bromine is larger than chlorine and can better stabilize the negative charge that will be generated upon deprotonation. HBr is expected to be more acidic than HCl.
acetylene
C2H2
ethanol
C2H5OH
propylene
C3H6
Butane
C4H10
phenol
C6H5OH
acetic acid (ethanoic acid)
CH3COOH
dimethyl ether
CH3OCH3 or C2H6O (Same molecular formula as ethanol)
methanol
CH3OH
carboxyl group
COOH
is nh3 or ch4 more acidic
Carbon and nitrogen are in the same row of the periodic table, so we must compare their electronegativity values. nitrogen is more EN so it is better able to stabilize a negative charge that will be generated upon deprotonation. Therefore, NH3 is expected to be more acidic than CH4.
exothermic reactions
Chemical reactions that release a significant amount of heat. change in H (enthalpy ) is neg atoms have smaller enthalpy as products
Alkenes
CnH2n ,Hydrocarbons that contain double covalent bonds
ethyl alcohol
Ethanol/grain alcohol; Skin degermer and antiseptic, surfactant action, disinfect electrodes and face masks A primary alcohol
four factors that affect the stability of negative charges
Generally speaking, the order of priority is the order in which the factors were presented: 1. Atom. Which atom bears the charge? (How do the atoms compare in terms of electronegativity and size? Remember the difference between comparing atoms in the same row vs. atoms in the same column.) 2. Resonance. Are there any resonance effects that make one conjugate base more stable than the other? 3. Induction. Are there any inductive effects that stabilize one of the conjugate bases? 4. Orbital. In what orbital do we find the negative charge for each conjugate base? A helpful way to remember the order of these four factors is to take the first letter of each factor, giving the following mnemonic device: ARIO
sulfuric acid
H2SO4 (Strong Acid) a source of protons concentrated sulfuric acid is an aqueous mixture of h2so4 and h2o acid present in the solution is actually h3o+ because of the leveling effect. that is, h3o+ is a weaker acid than h2so4, so the protons are transferred from h2so4 to water, giving a high concentration of h3o+`
which one has a higher BP: HOCH2CH2CH2CH2OH CH3OCH2CH2CH2OH
HOCH2CH2CH2CH2OH
change in H
Heat of reaction measures the change in enthalpy of the atoms of the reactants as they are converted to products
teflon
One of the earlier plastic to be developed in 1938, a du pont trade name for the white, soft, waxy, and non-adhesive polymer of tetrafluoroethylene. very low polarizability of fluorine atoms make this compound have small dispersion forces and thus notoriously low bPs
inductive effects
The acidity of H-A increases with the presence of electron-withdrawing groups in A. electronic effects transmitted through BONDS. The inductive effect of a group can be electron donating or electron withdrawing. iNDUCTIVE EFFECT weakens as the distance from the group increases in the case of ethyl fluoride (ch3ch2F), the positive charge that the fluorine imparts to the carbon closest to is is greater than that imparted to C2
hydrogen bonds
Very weak bonds BUT very STRONG dipole-dipole attractions; occurs when a hydrogen atom in one molecule is attracted to the electrostatic atom in another molecule when hydrogen atoms bonds to a small, strongly electronegative atoms (O, N, and F) hydrogen bonds hold the base pairs of double-stranded DNA together
ACETIC ACID IS A
WEAK ACID
Why is water a great solvent?
Water's polarity allows it to chemically bond to many different types of compounds and/or molecules. positive ions i.e are surrounded by water molecules with the negative end of the water dipole point toward the positive ion
aspirin is an example of an acid that achieves biodistribution asa result of it's ability to lose a proton (acid). Explain.
consider the journey that aspirin takes after you ingest it. This journey begins in your stomach, where the pH can be as low as 2. Under these very acidic conditions, aspirin is mostly in its uncharged form. That is, there is very little of the conjugate base present. The uncharged form of aspirin is absorbed by the nonpolar environment of the gastric mucosa in your stomach and the intestinal mucosa in the intestinal tract. After passing through these nonpolar environments, the molecules of aspirin enter the blood, which is a polar (aqueous) environment with a pH of approximately 7.4. At that pH, aspirin exists mainly in the charged form (the conjugate base), and it is distributed throughout the circulatory system in this form. Then, in order to pass the blood-brain barrier, or a cell membrane, the molecules must be converted once again into the uncharged form so that they can pass through the necessary nonpolar environments. The drug is capable of successfully reaching the target because of its ability to exist in two different forms (charged and uncharged). This ability allows it to pass through polar environments as well as nonpolar environments.
carboxylic acids, esters, and amides all
contain a carbonyl group that is bonded to an oxygen or nitrogen atom
Alkanes
contains only a single bond CnH2n+2
as bond strength increases, acidity ______
decreases
bond strength to the proton
decreases as we move down the column of the periodic table, increasing its acidity
proton acidity increases as we descend a column in the periodic table due to
decreasing bond strength to the proton
If the pH of a solution is greater than the pka of a compound, the compound is likely to be
deprotonated
why does methane, a nonionic nonpolar substance become a liquid or solid at all
disperson (london) forces!
the relative acidities of ethyne, ethene, and ethane parallels the
effective electronegativity of the carbon atom in each compound (electronegativity of carbon in ethyne is greater than the carbon in both the ethene and ethane)
potential energy exists between objects that
either attract or repel each other
any _____ atom can act as a lewis acid
electron deficient