polarity
A Carbon - Hydrogen system is always _______.
nonpolar
Rank the strengths of IMFs from strongest to weakest.
ion-dipole > hydrogen bonding > dipole-dipole > LDF
Name a phase change that has a negative delta H.
freezing, deposition, condensation
Which IMF is responsible for making a solution?
ion-dipole
The electronegativity trend increases from _____ to ____ and _____ to ____. What is the most electronegative atom?
left to right; bottom to top; Fluorine (F)
Which molecule has a dipole moment greater than zero?
a. CH3OH
b. CH3
c. CH3CH2CH3
d. CCl4
CH3OH
Ammonia (NH3) can form ____ hydrogen bonds and water (H2O) can form ____ hydrogen bonds.
one (1); two (2)
vaporization, fusion, sublimation
When forming an ion-dipole (think A---B where A = H2O and B = NaCl), the reaction is ________ (endothermic/exothermic) and delta H is _____ (positive/negative).
exothermic; negative
Draw the Lewis dot structure for SO2. Include dipole arrows and assign partial charges. Don't worry about resonance. Determine if the molecule is polar or nonpolar.
{answer on mini whiteboard}
When drawing Lewis dot structures, the _____ electronegative atom is in the center.
least
Which molecule would you expect to have the lowest boiling point?
a. CH3
b. CH3CH2
c. CH3CH2CH3
d. CH3CH2CH3CH2
CH3
Normal boiling point occurs at _____ atm.
one (1)
When delta H soln is negative, the reaction is __________ (endothermic/exothermic). delta H solv-solv and H solu-solu are ________ (greater/less than) than delta H solv-solu.
exothermic; less than
The higher the lattice energy, the _____ (harder or easier) it is to dissolve/separate ions.
harder
Nonpolar molecules have a dipole moment ______ zero. Polar molecules have a dipole moment ____ zero.
equal to; not equal to
All of the following can have a dipole moment greater than zero except:
a. CH3CN
b. C2H5OH
c. C2H4O
d. C2H6
C2H6
Which phase changes involve breaking IMFs? Which phase changes involve forming IMFs?
breaking: vaporization, sublimation, fusion (melting)
forming: condensation, deposition, freezing
When delta H soln is positive, the reaction is __________ (endothermic/exothermic). delta H solv-solv and H solu-solu are ________ (greater/less than) than delta H solv-solu.
endothermic; greater than
The two conditions for low solubility are:
1. strong lattice
2. weak hydration energy
Which two molecules are both nonpolar?
a. CO2 & H2O
b. H2O & CCl4
c. CCl4 & NH3
d. CO2 & CCl4
CO2 & CCl4
As IMF increases, __________ decreases.
vapor pressure
DAILY DOUBLE
Why does delta H vap require more energy than delta H fusion?
delta H vap requires more energy than delta H fusion because gas has no IMF, so all IMFs in liquids must be destroyed.
Why isn't oil and water considered a solution?
Oil and water are immiscible. They do not form a homogenous mixture.
FINAL JEOPARDY (discuss with team to determine how many points you want to bid)
Which of the following should have the highest vapor pressure?
a. C4H10, boiling point: -1 C
b. CH2Cl2, boiling point: 39.6 C
c. CH3CH2OH, boiling point: 78.2 C
d. H2O, boiling point: 100 C
C4H10