Boiling Point
Which has the higher boiling point? NH3 or CH4?
NH3
What is the amount of heat required to vaporize 1 mole of a liquid to a gas?
Heat of vaporization
Which Intermolecular Force is found in every molecule?
Dispersion Force
What describes a substance easily evaporated at normal temperatures?
volatile
What is the strongest intermolecular force present in liquid bromine?
Dispersion
The boiling point of CH4 is much lower than that of HF. This is because of what?
Hydrogen bonding in HF
How much heat is required to vaporize 4.8g of H2O?
11 kJ
Dipole-dipole forces are only present in molecules that are what?
Polar
What is the spontaneous flow of liquid into a narrow tube?
Capillary action
What is salad dressing an example of?
Miscibility
Which of the following molecules has the highest boiling point?
a) CH3CH2CH2CH3
b) CH3CH2CH2OH
c) CH3CH2CH2Cl
d) CH3CH2CH2SH
b) CH3CH2CH2OH
How much heat is required to vaporize 125g of C6H6 (benzene)? The heat of vaporization of benzene is 30.8 kJ/mol.
49.3 kJ
Hydrogen Bonds consist of Hydrogen plus what 3 elements?
Nitrogen, Oxygen, and Fluorine
What is a state of balance between continuing processes?
Dynamic equilibrium
Why does water have a very high surface tension?
Because of the strong intermolecular forces present in water.
Which has the higher boiling point? CS2 or CO2?
CS2
A 50.0 mL sample of water is heated to its boiling point. How much heat in kJ is required to vaporize it? (Assume a density of 1.00 g/mL.)
113 kJ
Which force(s) are present in CS2?
Dispersion
What is viscosity?
The resistance of a liquid to flow
How does a liquid develop a vapor pressure?
A fraction of the molecules of the liquid have enough kinetic energy to escape into the gas phase.
Rank the following elements from lowest boiling point to highest boiling point:
CH4O
CH4
CH3OCH3
CaCO3
CH4 < CH3OCH3 < CH4O < CaCO3
A 100.0 mL sample of water is heated to its boiling point. How much heat (in kJ) is required to vaporize it? (Assume that the density of the water is 1.00 g/mL and that ∆Hvap = 40.7 kJ/mol)
226 kJ
What force(s) are present in CH3Cl?
Dispersion, Dipole-dipole
What's the difference between adhesion and cohesion?
Adhesion - the attraction of unlike molecules
Cohesion - the attraction of like molecules
When a thin glass tube is put into water, the water rises 1.4 cm. When the same tube is put into hexane, the hexane rises only 0.4 cm. Explain.
The surface tension is much stronger (more adhesive) in water due to its polarity and hydrogen bonds