Exam 8: Effects of Intermolecular Forces

The figure shows the unit cell of a compound containing A (open spheres) and X (shaded spheres). What is the empirical formula of this compound if the shaded spheres form a face-centered cubic arrangement and the open spheres are contained within the unit cell?

The face-centered cubic unit cell to the right has been shaded to add clarity; the balls in the corners are black: those in the faces are gray. If the corners of the unit cells are at the center of the corner spheres, how many atoms are in one unit cell?

Sketch a phase diagram for hydrazine locating all points given: normal melting point (1.4˚C), normal boiling point (113.5˚C), critical point (380˚C, 145 atm), triple point (2.0˚C, 3.4 mm Hg)

Arrange the following in order of increasing vapour pressure at room temperature: 1) H₂O, 2) Hg, 3) Br₂, 4) CH₃CH₂OH

Na⁺ has an ionic radius of 116 pm and Cl^- an ionic radius of 167 pm. Estimate the volume of a NaCl unit cell.

The leaves of the lotus plant are extremely hydrophobic. That is, water does not stick to the leaves. In 2004, scientists were able to replicate this phenomenon on a film. Sketch what you think the meniscus of water would look like in a tube made of this material? What would the meniscus look like for oil?

Which type of solid is the most densely packed?

Draw molecular pictures that illustrate and explain the different polarizabilities of CH₂Cl₂ and CHCl₃.

Below is the structure for zinc sulphide. If the zinc atoms (zinc) are contained within the unit cell and the sulphur atoms (clear) form a face-centered cubic structure, how many sulphur atoms must be contained within the unit cell to balance the charge?

Arrange the following in order of increasing vapour pressure at room temperature. 1) CH₃OCH₃, 2) CH₃CH₂OCH₂CH₃, 3) CH₃C(O)CH₃, 4) CH₃CH₂OH

Describe how trees are able to transport water from their roots to the leaves on their branches high in the air.