Term
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Definition
| bonds between atoms such that the electrons are more strongly attracted by one atom than the other such that the electron distribution between atoms is not symmetrical |
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Term
δ
indicate what this is used for |
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Definition
lower case Greek letter delta
used to indicate partial charge |
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Term
|
Definition
| partial positive charge, used for electron poor atom |
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Term
|
Definition
| partial negative, used for electron rich atom |
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Term
| bond polarity is due to... |
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Definition
| differences in enegativity (EN) |
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Term
|
Definition
| an atom's ability to attract electrons |
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Term
| periodic trend in electronegativity |
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Definition
| increases as you go northeast |
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Term
| electronegativity difference in covalent bonds |
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Definition
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Term
| electronegativity difference in polar covalent bonds |
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Definition
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Term
| electronegativity difference in ionic bonds |
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Definition
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Term
| depiction of how arrows are used to indicate electron distribution |
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Definition
[image]
This is a crossed arrow, with the arrow pointing to the negative end and the other end being crossed to indicate positive end. Electrons are displaced in the direction of the arrow. |
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Term
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Definition
| the shifting of electrons in a δ bond in response to the electronegativity of nearby atoms |
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Term
| partial charge on atom or bong? |
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Definition
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Term
| molecular polarity results from... |
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Definition
| the vector summation of all individual bond polarities and lone-pair contributions in the molecule |
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Term
| net molecular polarity is measured by... |
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Definition
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Term
|
Definition
| the magnitude of the charge Q at either end of the molecular dipole times the distance r between the charges |
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Term
| how to calculate dipole moment |
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Definition
μ = Q X r
μ = dipole moment (C • m)
Q = magnitude of charge (C)
r = distance between charges (m) |
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Term
| how dipole moments are expressed in SI |
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Definition
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|
Term
1 D = ______ coulomb meters (C • m)
D = debye |
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Definition
| 3.336 X 10-30 coulomb meters (C • m) |
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Term
| some elements with substantially different enegativities from C |
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Definition
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Term
| effect of lone pairs on dipole moment |
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Definition
| lone pairs can alter the direction of the dipole moment |
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Term
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Definition
| the charge on a particular atom in a molecule if that atom was by itself |
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Term
| what formal charges are used for |
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Definition
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Term
| why it's helpful to identify and calculate formal charges correctly |
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Definition
| because they can give clues about chemical reactivity |
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Term
|
Definition
| individual structural forms of a resonance hybrid |
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Term
| the only difference between resonance forms |
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Definition
| the placement of the π and nonbonding valence electrons |
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Term
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Definition
| molecule that can't be represented adequately using a single line structure and must instead be considered as an average of 2 or more resonance forms |
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Term
| rules for resonance forms |
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Definition
1: Individual resonance forms are imaginary, not real.
2: resonance forms differ only in the placement of their π or nonbonding electrons
3: different resonance forms of a substance don't have to be equivalent
4: resonance forms obey normal rules of valency
5: the resonance hybrid is more stable than any individual resonance form |
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Term
| the real structure of resonance forms |
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Definition
| a composite, or resonance hybrid |
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Term
| how the movement of electrons is represented on drawings |
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Definition
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Term
| # of resonance forms vs. stability of substance and why |
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Definition
| the more resonance forms, the more stable the substance because its electrons are spread out over a larger part of the molecule and are closer to more nuclei |
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Term
| a useful technique for drawing resonance forms |
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Definition
| in general, any 3 atom grouping with a p orbital on each atom has 2 resonance forms |
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Term
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Definition
| atom that contains a single unpaired electron |
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Term
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Definition
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Term
|
Definition
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Term
| conjugate base (Brønstead-Lowry) |
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Definition
| the ion that results when an acid loses a proton |
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Term
| conjugate acid (Brønstead-Lowry) |
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Definition
| the ion that results when a base gains a proton |
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Term
| how acids and bases interact in the general sense |
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Definition
| acid + base <--> conjugate base + conjugate acid |
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Term
| how water can act as an acid or a base |
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Definition
| by accepting (base) or donating (acid) a proton |
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Term
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Definition
| measures the exact strength of a given acid in water |
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Term
| how to calculate acidity constant (Ka) |
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Definition
| Ka = ([H3O+][CB])/([acid])
Ka = acidity constant
CB = conjugate base |
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Term
|
Definition
| negative common logarithm of the Ka |
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Term
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Definition
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Term
| size of pKa vs. size of Ka |
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Definition
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Term
| size of pKa for stronger acid |
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Definition
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Term
| size of Ka for stronger acid |
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Definition
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Term
| size of pKa for weaker acid |
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Definition
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|
Term
| size of Ka for weaker acid |
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Definition
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|
Term
| some acids in order of size of pKa (highest to lowest)
refer to video to complete the list |
|
Definition
| -R (group of C's and H's)
-ammonia (NH3) and R2NH2NH3
-water and ROH
-Hydronium (H3O+)
-[image]
-HCl, HBr, H2SO4 |
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Term
| acid strength vs. strength of conjugate base |
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Definition
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Term
| the direction the proton goes in an acid-base reaction goes |
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Definition
| from the stronger acid to the stronger base |
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Term
| where the strong acids and bases and weak acids and bases must be in an acid-base reaction |
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Definition
| starting acids and bases should be stronger and ending acids and bases should be weaker |
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Term
| how to convert pKa into Ka |
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Definition
| Ka = 10-pKa
write it in scientific notation |
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Term
| organic acids are characterized by... |
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Definition
| the presence of a positively polarized H atom |
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Term
| the 2 main kinds of organic acids |
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Definition
-those that contain a H atom bonded to an electronegative O atom (O-H)
-those that contain a H atom bonded to a C atom next to C=O bond (O=C-C-H) |
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Term
| some ways anions can be stabilized |
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Definition
-having a negative charge on a highly electronegative atom
-resonance |
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Term
| why organic acids with O-H bonds are acidic |
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Definition
| because the conjugate base is stabilized by having its negative charge on a strongly electronegative atom |
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Term
| why organic acids with C=O bonds are acidic |
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Definition
| because the conjugate base is stabilized by resonance |
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Term
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Definition
| organic acids that contain the -CO2H grouping |
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Term
| organic bases are characterized by... |
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Definition
| the presence of an atom with a lone pair of electrons that can bond to H+ |
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Term
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Definition
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Term
|
Definition
donates an electron pair
has pair of nonbonding electrons that it can use to bond to a Lewis acid |
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Term
| what happens to the electron pair in the interaction of Lewis acids and bases? |
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Definition
| it is shared in a covalent bond |
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Term
| why metal cations can be Lewis acids |
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Definition
| because they accept a pair of electrons when they bond to a base |
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Term
| why some metal compounds can be Lewis acids |
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Definition
| because they have unfilled valence orbitals and can accept electron pairs from Lewis bases |
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Term
| why most O and N containing organic compounds act like Lewis bases |
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Definition
| because they have lone pairs of electrons |
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Term
| if an acid-base rxn forms a complex, can it go back and forth? |
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Definition
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Term
| other than bonds within molecules, this is also important in chemical reactions |
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Definition
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Term
|
Definition
interactions between molecules
aka intermolecular forces and van der Waals forces |
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Term
| types of noncovalent interactions between molecules |
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Definition
-dipole-dipole forces
-(London) dispersion forces
-H bonds |
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Term
|
Definition
they occur between polar molecules as a result of electrostatic interactions among dipoles
-can be attractive or repulsive depending on orientation of the molecules
-attractive predominates because it's lower in energy |
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Term
| dipole-dipole forces can be attractive or repulsive depending on... |
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Definition
| orientation of the molecules |
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Term
| attractive dipole-dipole forces predominate because... |
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Definition
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|
Term
| depiction of attractive and repulsive dipole-dipole forces |
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Definition
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Term
| (London) dispersion forces |
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Definition
| occur between all neighboring molecules and arise because the electron distribution within molecules is consistently changing |
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Term
| what causes dispersion forces in nonpolar molecules? |
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Definition
| dipole moments that are caused by consistently changing electron distribution |
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Term
|
Definition
| attractive interaction between a H bonded to an O or N atom and an unshared electron pair on another N or O atom |
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Term
| depiction of (London) dispersion forces |
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Definition
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Term
|
Definition
|
|
Term
| what causes water to be liquid at standard temperatures? |
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Definition
|
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Term
| what makes a sugar molecule hydrophilic? |
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Definition
| the -OH groups in its structure that enable it to form H bonds |
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Term
| what makes vegatable oil hydrophobic? |
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Definition
| has no groups that have H bonds, so it's limited to (London) dispersion forces |
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Term
|
Definition
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Term
| magnitude of charge in ionic bonds |
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Definition
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Term
| what the pKa of an acid must be to react almost completely with water |
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Definition
| at least 3 units lower than that of water
the pKa of water is 15.74; therefore, the pKa must be 12.74 or less |
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Term
|
Definition
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Term
| how to calculate pH using molarity (M) and pKa |
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Definition
| 1: find Ka
2: plug M and Ka into the Ka formula
3: solve for neumerator
4: plug what you get into the pH equation |
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Term
| what does an acid need to have if it wants to significantly react with the salt of another acid? |
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Definition
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Term
| why reactions of the same chemical can yield different results |
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Definition
| change in distribution of electrons caused by resonance |
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Term
| one reason two acids that contain an OH group can have differing acidity |
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Definition
| because one is better able to be stabilized by resonance, i.e., more resonance structures |
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Term
| can resonance contribute to whether or not a molecule or ion has a dipole moment? |
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Definition
if uniform, then no
if not uniform, then it could |
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Term
| why an O atom with 2 single bonds can have a dipole moment |
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Definition
| because of the lone pair electrons, which contribute its tetrahedral shape |
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Term
| in which direction are acid-base reactions favored? |
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Definition
| the direction in which the pKa pf the acid increases |
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Term
| why CH3CH2CH2OH has a higher boiling point than CH4 |
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Definition
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Term
| when a molecule has H bonding and dipole moments, which contributes greater to interactions with other molecules? |
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Definition
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Term
| how more electronegative elements can increase the acidity of organic acids that contain an O-H bond |
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Definition
| pulling electrons, the effect going down the chain, ultimately weakening the O-H bond |
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Term
| example of how to draw a 3D representation of a tetrahedral molecule |
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Definition
[image]
especially note that the wedge and dotted line have to track together; one is essentially hiding behind the other |
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Term
| example depiction of bond polarity and dipole moment |
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Definition
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Term
how the length of the nonpolar zig-zag line on these 2 molecules affects the dipole moment
[image] |
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Definition
| the longer the nonpolar zig-zag line, the lower the net dipole moment |
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Term
| does the sigma system change when drawing resonance structures? |
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Definition
|
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Term
| the difference between resonance forms |
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Definition
| where you put the pi electrons |
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Term
| when drawing resonance forms, never mess with... |
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Definition
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Term
| one thing that can make one resonance form more prominent than the other |
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Definition
| electronegativity of a certain atom |
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Term
| the absence of this system makes a molecule or ion unable to have resonance |
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Definition
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Term
| the most important thing to look for when determining which resonance form is better than the other |
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Definition
| whether or not atoms obey the octet rule; this supersedes electronegativity |
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Term
| what it means when one resonance form is better than the other |
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Definition
| the actual thing looks more like one than the other |
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Term
| rules for assessing which resonance structures are the best representations |
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Definition
1: the most important resonance contributors have the greatest numbers of filled octets
2: the structure with fewer formal charges is the better representation
3: electronegativity of specific elements |
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Term
| when all resonance structures for a particular molecule or ion are equally good representations of it, they are... |
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Definition
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Term
|
Definition
| measures involvement of s orbital as part of the hybrid |
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Term
| s-character of an sp3 hybridized atom |
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Definition
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|
Term
| s-character of an sp2 hybridized atom |
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Definition
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|
Term
| s-character of an sp hybridized atom |
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Definition
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|
Term
| importance of s-character |
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Definition
| the higher an atom's s-character, the higher its electronegativity |
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Term
| length of C-C bond vs. strength of bond |
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Definition
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Term
|
Definition
|
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Term
|
Definition
| completely dissociates in water |
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Term
| why ionic compounds (salts) will dissolve in water |
|
Definition
| because water supports the presence of ions |
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Term
| why salts won't dissolve in nonpolar solvents |
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Definition
| because the nonpolar solvent has no "handle" to grab onto ions |
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Term
|
Definition
|
|
Term
| this is constant once e'librium is established |
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Definition
| c'trations of products and reactants |
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Term
|
Definition
| no, because you can't have negative c'trations |
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Term
| relationship between ΔG and Keq |
|
Definition
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|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| why is a proton more likely to dissociate from O than from C? |
|
Definition
| because O is more e'negative |
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Term
|
Definition
|
|
Term
| what R is used to represent |
|
Definition
| collection of H's and C's |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Keq = ([CA][CB]) / ([A][B]) |
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|
Term
| once e'librium is established, the side containing which base will be favored? |
|
Definition
the side containing the more stable base
a base that undergoes resonance could be the more stable base |
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|
Term
| pKa of this molecule
[image] |
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Definition
|
|
Term
| when you go down a column on the PTable, e'negativity gives way to... |
|
Definition
|
|
Term
|
Definition
| the ability to obtain an induced polarity |
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Term
| PTable trend in polarizeability |
|
Definition
| the further down you go down the column, the more polarizeable |
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Term
| how polarizeability affects strength of acid |
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Definition
| the more polarizeable the element from which an anion is derived, the stronger the acid |
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Term
| why acids containing more polarizeable elements tend to be more acidic |
|
Definition
| because the anion derived from a more polarizeable element tends to be more stable than that derived from a less polarizeable anion |
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Term
| polarizeability of an element vs. the stabylity of its anion |
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Definition
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|
Term
| depiction of an endothermic reaction for an endothermic reaction |
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Definition
|
|
Term
| the 2 commandments of resonance |
|
Definition
1: don't break any single bonds
2: don't exceed an octet for 2nd row elements |
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Term
| questions to ask once resonance is established |
|
Definition
1: can we convert any lone pairs into pi bonds without violating the two commandments?
2: can we convert any pi bonds into lone pairs without violating the 2 commandments?
3: can we convert any pi bonds into pi bonds without violating the 2 commandments? |
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Term
| rules for assessing the relative importance of a resonance structure |
|
Definition
1: the most important resonance forms have the greatest number of filled octets
2: the structure with fewer fortmal charges is more important
3: other things being equal, a structure with negative charge on the more electronegative element will be more important
4: resonance structures with equally good Lewis structures are described as equivalent and contribute equally to the resonance hybrid |
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|
Term
| some factors that affect stability of conjugate bases |
|
Definition
1: atom - what atom is the charge on?
2: resonance - does resonance make one conjugate base more stable than the other?
3: induction - are any conjugate bases stabilized by inductive effects?
4: orbital - in what orbital do we find the negative charge for each conjugate base? |
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|
Term
| an ac id's willingness to give up a proton is affected by... |
|
Definition
| stability of that bond between the H and the other atom |
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|
Term
| trend in the ability of an element to stabilize charge |
|
Definition
| increases as you go down the column |
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|
Term
| why HI would be more willing to give up its proton, i.e., more acidic, than HF |
|
Definition
| because I has a larger volume over which to spread the charge, tius being more stable when it gives up its proton |
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|
Term
| why resonance is such a stabilizing force |
|
Definition
| because a delocalized negative charge is more stable than a localized negative charge |
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|
Term
| if the conjugate base of one acid has resonance and the other one doesn't, which acid will be more acidic? |
|
Definition
|
|
Term
| induction (acid-base context) |
|
Definition
| the pulling of electron density caused by differences in electronegativity |
|
|
Term
| how orbital affects acidity of an atom |
|
Definition
| sp orbitals tend to be more stable than sp2 and sp3 or bitals because sp orbitals tend to have their electrons closer to the nucleus |
|
|
Term
| which H is more acidic: H bonded to sp3 hybridized N or H bonded to sp hybridized C? |
|
Definition
| H bonded to sp hybridized C |
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|
Term
|
Definition
| the effect of CH groups hindering interaction with the solvent |
|
|
Term
|
Definition
| shows how the electrons move during a reaction to form the products |
|
|
Term
| how to show the mechanism of an acid-base rxn |
|
Definition
draw an arrow to indicate floe of electrons from Lewis acid to
Lewis base |
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|
