Chem 2 cp intermolecular forces

Liquid A has a boiling point of 96 ̊C and liquid B has a boiling point of 68 ̊C. Which of the following is true?

B must have weaker intermolecular forces of attraction. - because it's more volatile

Explain why propane (C3H8) is a gas at room temperature and hexane (C6H14) is a liquid at room temperature.

Both are nonpolar substances with London dispersion forces, but C6H14 is more massive so its London dipersion forces are stronger, holding the molecules closer together, resulting in a liquid at room temperature.

Which of the following would exhibit hydrogen bonding?

CH3OH

Which of the following would have the highest vapor pressure at 0°C?

CH4

How do the boiling points of these substances compare? Rank them from the lowest to the highest boiling point. Defend your answer with scientific reasoning (reference specific intermolecular forces). H2O, CH3Br, CH4, C4H10

CH4 = London dispersion forces only and a low mass = lowest boiling point C4H10 = London dispersion forces only, but a larger mass = low boiling point CH3Br = London dispersion forces and dipole-dipole forces = higher boiling point H2O = London dispersion forces, dipole-dipole forces, and hydrogen bonding = highest boiling point

London dispersion forces are the only attractive intermolecular forces in which compound?

CO2

Which of the following substances is most likely to exist as a gas at room temperature and normal atmospheric pressure: P4O10, F2, AgCl, I2? WHY?

F2 - it is nonpolar which means it only has London dispersion forces and it is less massive than I2 so its London dispersion forces are weaker than those in I2, therefore F2 evaporates the easiest (the particles are not held together by intermolecular forces).

Which of the following substances would have the highest boiling point?

I2

At normal atmospheric pressure and a temperature of 0 °C, which phase(s) of water can exist?

Ice and water

Which of the following explains why, at room temperature, I2 is a solid, Br2 is a liquid, and Cl2 is a gas?

London dispersion forces

Which of the following substances would you expect to have the lowest boiling point?

Methane CH4 - it's nonpolar - London dispersion forces only

Which of the following molecules has a dipole moment?

PCL3

What are some characteristics of high-viscosity liquids? Describe the properties itemized.

Strength of intermolecular forces High viscosity liquids have strong intermolecular forces.

H2S is a gas at room temperature while H2O is a liquid. What can explain this difference?

The greater electronegativity of O allows hydrogen bonding in H2O.

1. Explain the trend displayed in the boiling points in the table below (your answer must include reference to an intermolecular force and the reason for the trend). Noble Gas Boiling Point (K) He=4.6 Ne=27.3 Ar=87.5 Kr=120.9 Xe=166.1

The noble gases are all nonpolar, and so, the only intermolecular forces are London dispersion forces. London dispersion forces increase with increasing mass (size), and the stronger the intermolecular forces the higher the boiling point.

Which one of the following statements is incorrect?

The stronger the intermolecular forces, the higher the vapor pressure.

Liquid X has a vapor pressure of 100 torr at 25 oC, and liquid Y has a vapor pressure of 40 torr at 25 oC. Which of the following is true?

X is more volatile than Y.

The normal boiling point of liquid X is less than that of liquid Y, which is less than that of liquid Z. Which of the following is the correct order of increasing vapor pressure of the three liquids?

Z, Y, X

The critical temperature of a substance is the - - -

highest temperature at which a substance can exist in the liquid state, regardless of pressure.

Which of the following substances would you expect to have the lowest boiling point?

molecular Fluorine, F2

When the liquid metal mercury, Hg, is placed in a small tube, the meniscus actually curves upward, just the opposite of water. The reason is that - - -

the cohesive force is greater than the adhesive force.

When the liquid metal mercury, Hg, is placed in a small tube, the meniscus actually curves upward, just the opposite of water. The reason is that ...

the cohesive force is greater than the adhesive force.