13. Liquids, Solids & Intermolecular Forces

What is the major electrostatic force found between ammonia molecules, NH₃?

As it cools off, olive oil slowly hardens and forms a solid over a range of temperatures. Which best describes it as a solid? 

Compound A is hard, doesn't conduct electricity, and melts at 1400ºC. Compound A represents which of the following:

Classify each solid as amorphous, molecular, network covalent, alloy or ionic. 

a) Steel                                               ______________________

b) CO₂                                                ______________________

c) Graphite                                         ______________________

d) CaCO₃                                            ______________________

e) Bronze, an alloy of Cu and Sn      ______________________

Which statement best describes why carbon can form a wide variety of organic compounds?

Consider the compound Al(OH)₃. What type of solid does it form? Crystal lattice, glass, metal, or molecule?

What type of crystalline solid is CH₃CH₂CH₂CH₃?

2. (a) Wc is an interstitial alloy. Describe its structure. (3 m

Silica is a chemical compound __________________

Can an ionic compound ever consist of a cation-cation or anion-anion bond

In what size range are materials considered to be “nanomaterials”?

The molecule p-azoxyanisole shown here transitions from a solid to a nematic liquid crystalline phase at 118°C and to a liquid at 135°C.

a. Will the phase transition that occurs upon heating from 130°C to 140°C be exothermic or endothermic?

b. Do you expect the viscosity to increase or decrease on heating from 130°C to 140°C?

It is not uncommon for molecules to adopt more than one type of liquid crystalline phase, with each phase appearing over a different temperature range. The molecule shown below, 4'-octyl-4-biphenylcarbonitrile, is one such example. The solid melts at 24°C and undergoes further phase transitions at 34°C and 43°C.

a. Based on the amount of molecular order found in the various types of liquid crystals, would you expect the phase that is stable between 24 and 34°C to be a nematic liquid crystal or a smectic A liquid crystal?

b. Could you determine if the phase transition at 43°C is to the liquid phase or yet another liquid crystal phase from the appearance of the sample?