Intermolecular Forces and Properties Review

Which of the following substances has the lowest boiling point?

• H₂

• Ne

• CO

• NH₃

Based on these structures, which isomer of 1, 2-dichloroethylene has the higher boiling point, and why?

• Isomer 1, because it has a molecular dipole, while isomer 2 does not

• Isomer 1, because its molecules are more compact than those of isomer 2

• Isomer 2, because it forms hydrogen bonds, while isomer 1 does not

• Isomer 2, because its molecules are less polarizable than those of isomer 1

Tags

NGSS.HS-PS1-3

Based on the information in the table above, which of the following best explains why ethylene glycol has a lower vapor pressure than 1-propanol?

• Ethylene glycol is less polarizable and has weaker dispersion forces than 1-propanol.

• Ethylene glycol has a larger molar mass than 1-propanol.

• Ethylene glycol forms more hydrogen bonds than 1-propanol.

• Ethylene glycol has weaker dipole-dipole forces than 1-propanol.

Which solid, CS₂(s) or CCl₄​(s), has the higher melting point, and why?

• CS₂(s), because CS₂ molecules are more polarizable than CCl₄ molecules

• CS₂(s), because C−S bonds are stronger than C−Cl bonds

• CCl₄​(s), because CCl₄​ molecules are more polarizable than CS₂ molecules

• CCl₄​(s), because C−Cl bonds are stronger than C−S bonds

The structure of a-Si a form of silicon commonly used in the manufacture of LCD screens, is shown above.

Based on the diagram above, which of the following can be concluded about a-Si?

• It is an amorphous network solid.

• It is an amorphous molecular solid.

• It is a crystalline network solid.

• It is a crystalline molecular solid.

Tags

NGSS.HS-PS1-3

Which of the following correctly lists the substances HCN, N₂, HF in order of increasing intermolecular forces?

• HCN < N₂ ​< HF

• N₂ < HCN < HF

• HF < N₂​ < HCN

• N₂​ < HF < HCN

A mixture containing 2.0mol CH₄ (g), 4.5mol O₂ (g), and

3.5mol Ne (g) exerts a total pressure of 0.80 atm.

What is the partial pressure of the CH₄ (g)?

• 0.16 atm

• 0.40 atm

• 0.64 atm

• 0.80 atm

A sample of Ar (g) is contained in a cylinder with a moveable piston at an initial temperature of T₁. The volume of the sample is decreased from 4.5 L to 1.5 L while the pressure is held constant, as shown in the diagram above.

What is the final temperature of the argon gas?

•  $\frac{T1}{6}$   
  

•  $\frac{T1}{3}$  

• T1

• 3T1

Assuming constant n and T, which of the following graphs correctly represents the relationship between P and V for an ideal gas?

• 
• 
• 
• 

A research scientist measures the pressure of a sample of NH₃(g) at 300 K and observes that it is lower than the pressure calculated using the ideal gas law.

This deviation in pressure most likely results from the:

• relatively small molar mass of NH₃

• low density of the NH₃ sample

• attractive forces among the NH₃ molecules

• nonzero volumes of the NH₃ molecules