Intermolecular Forces (3.1-3.3)

Which of the procedures outlined below can be used to change the boiling point of pure ammonia?

I. Increase the substances elevation by bringing it to the top of a mountain.

II. Add more ammonia to the container.

III. Increase the pressure on the surface of the liquid.

• I only

• I and II only

• I and III only

• III only

The boiling temperature of Ne is less than that of Kr. Which of the statements below indicates why this is so?

• Kr forms stronger dipole-dipole forces than Ne.

• Kr forms stronger hydrogen bonds than Ne.

• Kr is more polarizable than Ne.

• Kr forms stronger dipole induced-dipole bonds than Ne

Which of the following gases is most soluble in water at 1.0 atm?

• N₂(g)

• O₂(g)

• NO(g)

• H₂(g)

Potassium iodide has the lowest solubility in which of the following liquids?

• CH₃OH

• C₂H₅OH

• C₃H₇OH

• C₆H14

Which statement best describes why vegetable oil exists as a liquid at room temperature?

• The molecules have weak dipole-dipole forces due to the small electronegativity difference between neighboring carbon atoms.

• The molecules have weak London dispersion forces due to their relatively small size.

• The molecules are saturated

• The double bond between carbon atoms gives the structure a bent shape that reduces London dispersion forces.

Which of the oxides listed below exists as a gas at 298 K and 1.0 atm?

• NO₂

• CaO

• MgO

• SiO₂

Which of the following processes would produce the highest vapor pressure at 25^oC and 1 atm?

• NaCl(s) --> NaCl(g)

• Fe(s) --> Fe(g)

• NH₃(l) --> NH₃(g)

• PH₃(l) --> PH₃(g)

Which of the following best describes the process of writing on paper with a pencil?

• Sheets of carbon atoms that are bonded together in a trigonal planar geometry, producing a covalent network solid, slide overtop of one another as pi-bonds are broken.

• The weak intermolecular forces between lead atoms in the metallic solid sever, allowing the atoms to be deposited on the paper.

• Weak London dispersion forces between individual carbon atoms are broken, allowing them to be deposited on the paper.

• The carbon containing non-polar compounds in the pencil bond to the non-polar sections of the cellulose fibers on the paper with dispersion forces.

Refer to the graph above that depicts the temperature changes that occur as a certain pure substance is heated at a constant rate in an open container at 1 atm.

What is the normal boiling temperature for this substance?

• 50^oC

• 25^oC

• 87^oC

• 100^oC

Refer to the graph below that depicts the temperature changes that occur as a certain pure substance is heated at a constant rate in an open container at 1 atm.

Which of the following statements provides the best indication of what is occurring from t= 3 to t = 4?

• Gaseous particles are move further away from one another.

• The entire system is in the gas phase.

• The entire system is in the liquid phase.

• The vapor pressure of the liquid is increasing.