Question 1

Octane,C8H18,boils at 125°C,whereas water boils at 100°C.This information suggests that the dispersion forces in nonpolar octane molecules are stronger than the dispersion forces and hydrogen bonding in water.

Accepted Answer

A) True 
 B)False

Question 2

Based on the phase diagram of a pure substance given below,what change of state occurs as the substance changes from point C to point D?

Accepted Answer

A) The substance increases in temperature with a phase change from solid to liquid. 
B) The substance increases in temperature with a phase change from solid to vapor. 
C) The substance increases in temperature with a phase change from liquid to vapor. 
D) The substance increases in temperature but does not undergo a phase change. 
E) The substance increases in temperature and becomes a supercritical fluid.

Question 3

Which one of the following pure substance has both dispersion forces and dipole-dipole forces?

Accepted Answer

A) HCl 
B) BCl3 
C) Br2 
D) H2 
E) CO2

Question 4

What is another name given to dispersion forces?

Accepted Answer

A) ion-dipole interactions 
B) dipole-dipole interactions 
C) hydrogen bonding 
D) covalent forces 
E) London forces

Question 5

What is defined as the number of atoms surrounding an atom in a crystal lattice and indicates how tightly the atoms are packed together?

Accepted Answer

A) the unit cell 
B) the radius of the cubic cell 
C) the coordination number 
D) the area of the cubic cell 
E) the atoms themselves

Question 6

Which one of the following involves ion-dipole interactions?

Accepted Answer

A) Na+ and Cl- 
B) H+ and F- 
C) Na+ and Mg2+ 
D) two water molecules 
E) Na+ and H2O

Question 7

Which one of the following crystallizes in a metallic lattice?

Accepted Answer

A) C 
B) NaMnO4 
C) K 
D) LiClO4 
E) K2Cr2O7

Question 8

Which substance has the highest vapor pressure at room temperature?

Accepted Answer

A) HF 
B) HCl 
C) HBr 
D) HI 
E) All of these substances have the same vapor pressure at room temperature.

Question 9

Consider the phase diagram shown below.  a.What phase(s)is/are present at point A?
b.What phase(s)is/are present at point B?
c.Name point C and explain its significance.
d.Starting at D,if the pressure is lowered while the temperature remains constant,describe what will happen.

Accepted Answer

The answer of Consider the phase diagram shown below. ...

Question 10

The vapor pressure of ethanol is 400.mmHg at 63.5°C.Its molar heat of vaporization is 39.3kJ/mol.What is the vapor pressure of ethanol,in mmHg,at 34.9°C? (R = 8.314 J/K • mol)

Accepted Answer

A) 109 mmHg 
B) 220 mmHg 
C) 366 mmHg 
D) 376 mmHg 
E) 1470 mmHg

Question 11

______________ is the name given to the phase change from a solid directly to a gas.

Accepted Answer

The answer of ______________ is the name given to the...

Question 12

Vanadium crystallizes in a body-centered cubic lattice,and the length of the edge of a unit cell is 305 pm.What is the density of V?

Accepted Answer

A) 0.712 g/cm3 
B) 2.98 g/cm3 
C) 5.96 g/cm3 
D) 8.77 g/cm3 
E) 11.9 g/cm3

Question 13

The strongest intermolecular interactions between hydrogen fluoride (HF)molecules arise from

Accepted Answer

A) dipole-dipole forces. 
B) London dispersion forces. 
C) hydrogen bonding. 
D) ion-dipole interactions. 
E) ionic bonds.

Question 14

Which has the highest surface tension at a given temperature?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 15

Use the graph of vapor pressure to determine the normal boiling point of O2.

Accepted Answer

A) 92 K 
B) 90.K 
C) 88 K 
D) 84 K 
E) 78 K

Exam 11: Intermolecular Forces and the Physical Properties of Liquids and Solids

Octane,C₈H₁₈,boils at 125°C,whereas water boils at 100°C.This information suggests that the dispersion forces in nonpolar octane molecules are stronger than the dispersion forces and hydrogen bonding in water.