Deck 10: Molecular Interactions

Question 1

The dipole moment of hydrogen chloride, HCl, is 1.08 D and the bond length is 127 pm. Calculate the fractional charge on the hydrogen and chlorine atoms.

A) 8.50  10^-3 C
B) 2.84  10^-8 C
C) 2.84  10^-20 C
D) 2.84  10^-20 C
Title: Focus 10 - Question 02

Answer 1

C

Question 2

The Pauling electronegativities of chlorine and iodine are 3.0 and 2.5 respectively. Estimate the dipole moment of iodine monochloride, ICl.

A) 0.0 D
B) 0.5 D
C) 2.5 D
D) 3.0 D

Answer 2

B

Question 3

The dipole moment of nitrobenzene is 3.99 D. Estimate the magnitude of the dipole moment in meta (1,3-)dinitrobenzene.

A) 2.0 D
B) 3.0 D
C) 4.0 D
D) 8.0 D

Answer 3

C

Question 4

The atomic coordinates and partial charges for the planar molecule fluoroethene, C₂H₃F, are
Calculate the x and y components of the dipole moment.

A) _x = -4.72  10^-30 C m, _y = -1.33  10^-30 C m
B) _x = -0.295  10^-30 C m, _y = -0.083  10^-30 C m
C) _x = -7.27  10^-33 C m, _y = -1.28  10^-30 C m
D) _x = 1.10  10^-29 C m, _y = 2.96  10^-30 C m

Question 5

The dipole moment of an ozone molecule, O₃, is 0.53 D. The molecule has a symmetrical bent structure so that, if the molecule is assumed to lie in the yz plane, the terminal atoms have coordinates (0.678 Å,0,-0.362 Å) and the central atom has coordinates (0,0,0.724 Å). The terminal atoms have a net negative partial charge and the central atom has a net positive partial charge. Determine the magnitude of the partial charges on each of the oxygen atoms.

A) Terminal: -0.051e Central: +0.102e
B) Terminal: -0.076e Central: +0.076e
C) Terminal: -0.102e Central: +0.102e
D) Terminal: -0.108e Central: +0.215e

Question 6

Determine the strength of the electric field necessary to induce a dipole moment of1.0 D in sulfur hexafluoride, SF₆, which has been calculated to have a polarizability volume of 4.00 ų.

A) 1.7 kV m^-1
B) 6.2 kV m^-1
C) 95 kV m^-1
D) 7.5 kV m^-1

Question 7

Calculate the magnitude of the potential energy for the interaction of two co-linear hydrogen fluoride, HF, molecules whose centres are separated by 5.0 Å. The dipole moment of a hydrogen fluoride molecules is 1.91 D.

A) 1.9  10^-21 J
B) 12  10^-22 J
C) 5.8  10^-21 J
D) 2.9  10^-21 J

Question 8

Estimate the potential energy resulting from the dispersion interaction between two xenon, Xe, atoms at a separation of 4.80 Å. The polarizability volume of a xenon atom is 4.16 ų and the ionization energy is 12.1 eV.

A) -1.26  10^-22 J
B) -5.71  10^-3 J
C) -3.50  10^-22 J
D) -9.14  10^-22 J

Question 9

The mean separation between chlorine, Cl₂, molecules, at a temperature of 298.15 K and a pressure of 1 bar is 3.5 nm. Given the values of the Lennard-Jones parameters are  = 368 kJ mol^-1 and r_ = 412 pm, use the Lennard-Jones function to calculate the potential energy between pairs of xenon atoms at this separation.

A) -3.9 J mol^-1
B) 0.0 J mol^-1
C) -0.98 J mol^-1
D) -15 J mol^-1

Question 10

The Lennard-Jones parameters for the interactions between benzene, C₆H₆, molecules are  = 454 kJ mol^-1 and r₀ = 527 pm. Calculate the separation that corresponds to the minimum in the Lennard-Jones potential.

A) 592 pm
B) 527 pm
C) 1054 pm
D) 745 pm