Bonding Flashcards
Place the following in order from highest to lowest boiling point and explain why: ethanol, hexane, water, octane
Highest BP: Water Ethanol Octane Lowest BP: Hexane Boiling point is largely determined by intermolecular forces such as hydrogen bonding and London-dispersion forces. Water contains two sites of hydrogen bond donation as well as acceptance, so it will have the highest boiling point of the options provided. Ethanol is much smaller than octane but its ability to hydrogen bond will mean its boiling point is higher than both octane and hexane. Octane and hexane have the same weak intermolecular forces but because octane is larger, it will have the higher boiling point, as increased intermolecular interactions will require more heat energy to break.
When determining relative boiling and melting point, what properties of a substance should you consider first?
Intermolecular interactions- intermolecular interactions determine boiling and melting points. The more intermolecular interactions between molecules, the higher the BP. Water has a pretty high BP when compared to a completely non polar molecule.
Which are stronger- inter or intramolecular forces?
intra
Place the following intermolecular interactions in order from strongest to weakest: H-bonds, Ion-Dipole, Dipole-dipole, Ionic, london dispersion
Strongest: Ionic, ion-dipole H-bonds dipole-dipole London
Nitrate
NO3 -1
Nitrite
NO2 -1
Carbonate
CO3 -2
Bicarbonate
HCO3 -1
Perchlorate
ClO4 -1
Chlorate
ClO3 -1
Sulfate
SO4 -2
Sulfite
SO3 -2
Hydroxide
OH-
Chromate
CrO4 2-
Cyanide
CN-
Permagnate
MnO4 -1
Acetate
C2H3O2 -1
If the electronegativity difference between two atoms in a bond is less than 0.5, how would you classify it? Polar, nonpolar, or ionic?
Nonpolar
If the electronegativity difference between two atoms between 0.5 and 1.7, how would you classify it? Polar, nonpolar, or ionic?
polar
If the electronegativity difference between two atoms in a bond is greater than 1.7, how would you classify it? Polar, nonpolar, or ionic?
ionic
When naming ionic compounds, what are the general rules to remember?
-No prefixes -ends in “ide” -Trans metals use roman numerals -CaF2 is not calcium difluoride, its just calcium fluoride -name starts with cation
when naming covalent compounds, what are the general rules of thumb?
-Element names go in order of electronegativity unless it has carbon. Carbon is always first lol. -“ide” ending but they do use prefixes: mono, di, tri, tetra, penta -The only time when you don’t use prefix is when it is a mono and it is the first element like CO is not monocarbon monoxide, its just carbon monoxide
A mobile phase containing various solutes is run through a stationary phase containing crystals with amine (-NH2) groups. What groups would elute first and last and why?
Nonpolar solutes would be eluted first due to their weak interactions with the amine groups in the stationary phase. Polar protic solutes would be eluted last due to hydrogen bonding with the amine groups, and polar aprotic solutes would be eluted in the middle of the process. Note that “protic” simply references a solvent’s ability to hydrogen bond.
Polar or Nonpolar: C-H
Nonpolar covalent bond
Polar or Nonpolar: C-O
Polar covalent
Polar or Nonpolar: O-H
Polar covalent
What is a coordinate covalent bond?
A coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a kind of two-center, two-electron covalent bond in which the two electrons derive from the same atom. One atom donates both electrons.
Hemoglobin binds several molecules, leading to a conformational change of the protein. Of the molecules that hemoglobin binds, which is the LEAST polar?
NO
CO2
CO
2,3-BPG
Carbon dioxide
While carbon dioxide is comprised of two oxygen atoms that are much more electronegative than carbon, the molecule is linear, which makes it nonpolar.
