Choose the substance with the highest viscosity at a given T Group of answer choices CI4  (this is carbon tetraiodide)  CBr4 CF4 CCl4 CH4

The surface tension and viscosity of water at several different temperatures are given in this table. Water Surface Tension (mN/m) Viscosity (mPa s) 0 C 75.6 1.79 20 C 72.8 1.00 60 C 66.2 0.47 100 C 58.9 0.28 (a) As temperature increases, what happens to the surface tension of water? Explain why this occurs, in terms of molecular interactions and the effect of changing temperature. (b) As temperature increases, what happens to the viscosity of water? Explain why this occurs, in terms of molecular interactions and the effect of changing temperature.

Which of the following do you expect to be molecular solids? a silicon tetrachloride, SiCl4 b lithium bromide, LiBr c sodium fluoride, NaF d bromine chloride, BrCl

Identify the kinds of forces that are most important in holding the particles together in a crystalline solid sample of each of the following substances. (a) Kr (b) HF (c) K2O (d) CO2 (e) Zn (f) NH3

The CsCl structure is a simple cubic array of chloride ions with a cesium ion at the center of each cubic array (see Exercise 69). Given that the density of cesium chloride is 3.97 g/cm3, and assuming that the chloride and cesium ions touch along the body diagonal of the cubic unit cell, calculate the distance between the centers of adjacent Cs+ and Cl ions in the solid. Compare this value with the expected distance based on the sizes of the ions. The ionic radius of Cs+ is 169 pm, and the ionic radius of Cl is 181 pm.

Spinel is a mineral that contains 37.9% aluminum, 17.1% magnesium, and 45.0% oxygen, by mass, and has a density of 3.57 g/cm3.The edge of the cubic unit cell measures 809 pm. How many of each type of ion are present in the unit cell?

8.48 Why must the vapor pressure of a substance be measured only after dynamic equilibrium is established?

In terms of the kinetic molecular theory, in what ways are liquids similar to solids? In what ways are liquids different from solids?

Calculate the percent of volume that is actually occupied by spheres in a body-centered cubic lattice of identical spheres You can do this by first relating the radius of a sphere, r, to the length of an edge of a unit cell, l. (Note that the spheres do not touch along an edge but do touch along a diagonal passing through the body-centered sphere.) Then calculate the volume of a unit cell in terms of r. The volume occupied by spheres equals the number of spheres per unit cell times the volume of a sphere (4r3/3).

Pentylamine, CH3CH2CH2CH2CH2NH2, is a liquid that boils at 104C and has a viscosity of 10 10 4 kg/(m s). Triethylamine, (CH3CH2)3N, is a liquid that boils at 89C and has a viscosity of about 4 10 4 kg/(m s). Explain the differences in properties of these two compounds.