How do intermolecular forces differ from intramolecular forces?
Intermolecular forces are the forces BETWEEN molecules of a substance(s). They are always less than the intramolecular forces, which are within an individual molecule.
100
At the same temperature, describe the kinetic energy of a mole of a solid vs. a mole of a liquid.
At the same temperature, the kinetic energy of solids and liquids is the same.
100
Do liquids have a definite shape and volume? Explain.
Definite volume, no definite shape. Particles in a liquid can flow to shape of container, but cannot expand to fill it's container due to stronger intermolecular forces.
100
This describes the behavior of gases in terms of particles in motion.
Kinetic-molecular theory
100
When vaporization occurs only at the surface of a liquid, the process is called __________.
Evaporation
200
What are the 3 intermolecular forces we discussed?
1) dispersion forces
2) dipole-dipole forces
3) hydrogen bonds
200
Describe the density of solids.
In general, solids are more dense because they take up less space than liquids or gases. And density is equal to mass divided by volume, so you are dividing by a smaller number, which makes density increase.
200
Describe the fluidity of liquids compared to the fluidity of a gas.
A liquid diffuses more slowly than a gas at the same temperature because intermolecular forces are stronger in a liquid than a gas.
200
Do gas particles have significant attractive or repulsive forces between them? Why or why not?
The volume of the particles is small compared with the volume of the empty space. Because gas particles are far apart, there are no significant attractive or repulsive forces.
200
When will a substance start to boil?
When the vapor pressure of a liquid is equal to the external atmospheric pressure.
300
Explain why hydrogen bonds are stronger than most dipole-dipole forces.
A hydrogen bond involves a large difference in electronegativity between the hydrogen atom and the atom it is attached to, making the bond extremely polar. Additionally, the atoms the atoms in a hydrogen bond are small and very electronegative.
300
This is a solid whose atoms, ions or molecules are organized in an orderly, geometric, three-dimesional structure.
Crystalline solid
300
Give an example of a viscous liquid and describe a way to decrease it's viscosity.
Honey--heat it up
Ketchup--shear-thinning force--hit the bottle
300
Use kinetic-molecular theory to explain the relationship between the compression and expansion of gases.
Because of the space between gas particles, gases are easily compressed when pushed into a smaller volume. When the pressure is removed, their random motion enables gases to expand.
300
Give an example of a phase change that releases energy.
Deposition
Condensation
Freezing
400
What atoms can form a hydrogen bond?
Hydrogen bonded with: Fluorine, Oxygen, or Nitrogen
400
What would you expect the melting point of an ionic solid to be compared to that of a molecular solid? Why?
Ionic solids typically have a higher melting point than molecular solids because the ionic crystal lattice structure is strong due to attraction between the oppositely charged ions.
400
Describe surface tension and why it exists.
Surface tension is a measure of the inward pull by particles in the interior. The stronger the attraction between particles, the greater the surface tension.
400
What is the ratio of effusion rates of krypton and neon at the same temperature and pressure?
0.4931
400
This point on a phase diagram represents the temperature and pressure at which 3 phases of a substance can coexist.
triple point
500
What type of intermolecular bond exists in carbon monoxide? Draw an example of this bond.
dipole-dipole
500
Hypothesize why the surface of mercury in a thermometer is convex; that is, the surface is higher in the center.
The cohesion between mercury atoms is stronger than the adhesion between mercury and the glass of the thermometer.
500
Describe the difference between adhesion and cohesion by using a graduated cylinder of water as an example.
Adhesion describes the force of attraction between molecules that are different (water and the plastic graduated cylinder). Cohesion describes the force of attraction between identical molecules (water and water).
500
The pressure atop the world's highest mountain, Mount Everest, is usually 33.6 kPa. Convert the pressure to atmospheres (1 atm = 101.3 kPa). How does the pressure compare to the pressure at sea level?
0.332 atm; It is about 1/3 the pressure at sea level.
500
Describe where solids are located on a phase diagram.
They are located on the left, where there is the lowest temperature.