Exam 12: Intermolecular Attractions and the Properties of Liquids and Solids

The presence of which intermolecular force would lead to the highest viscosity within a liquid?

During a rain storm, the surface of a car hood gets wet. If the car has a good polish or has recently been waxed, the water tends to bead or form drops, instead of evenly covering the surface. What does this say about the properties of water and the wax used to protect the car hood?

What is the mass of a sample of iron that has 5.00 × 10²² unit cells, if the iron crystallizes in a body-centered cubic lattice? The molar mass of iron is 55.85 g mol^-1.Hint: Use dimensional analysis and the number of atoms per unit cell.

A low heat of vaporization indicates that a substance has ________ intermolecular forces in the liquid form.

An unknown solid is very hard with a very high melting point. It does not conduct electricity in either the solid or liquid phase. What kind of crystal best describes this solid?

Which of the following organic liquids would have the strongest surface tension?

Which of the following compounds should have the largest value for heat of vaporization ( $\Delta$ H_vap)?

A liquid which is kept in a pressure container at a temperature above its critical temperature is called a ________.

The following questions refer to the diagram below. -At what temperature and pressure will the species stop subliming (going from a solid to a gas)?

Boron nitride has the empirical formula BN, melts at 2967°C and is nearly as hard as diamond. Which category of substance does boron nitride most likely fit into?

The normal boiling point of acetic acid, HC₂H₃O₂, is 117.9°C, and its heat of vaporization is 39,690 J/mol. What is its vapor pressure at 100.0°C?

An unknown solid is soft and brittle with a low melting point. It does not conduct electricity in either the solid or liquid phase. What kind of crystal best describes this solid?

X-ray diffraction measurements on a newly discovered crystalline form of element X revealed that X crystallizes in a body-centered cubic lattice in which the unit cell edge length is 304.6 picometers. Calculate the atomic radius of the X atoms in this crystal, based on the assumption that the atoms are tightly packed in the unit cell.Hint: Find the length of the cell body diagonal using the Pythagorean theorem.

X-ray diffraction measurements on a newly discovered crystalline form of Eu revealed that Eu crystallizes in a body-centered cubic lattice in which the unit cell edge length is 458.3 picometers. Calculate the atomic radius of the Eu atoms in this crystal, based on the assumption that the atoms are tightly packed in the unit cell.Hint: Find the length of the cell body diagonal using the Pythagorean theorem.

In order to boil water, we need to supply heat. This is in order to

Describe the difference between molecular crystals and covalent crystals, in terms of types of bonding and physical properties.

Which compound should have the lowest boiling point?

What compound will not exhibit hydrogen bonding in the liquid state?

X-ray diffraction measurements revealed that Ni crystallizes in a face-centered cubic lattice in which the unit cell edge length is 352.4 picometers.Calculate the atomic radius of the Ni atoms in this crystal, based on the assumption that the atoms are tightly packed in the unit cell.Hint: Find the length of the cell face diagonal using the Pythagorean theorem.

What other molecular factors determine the viscosity of a liquid?