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Lesson: Physical Effects of Intermolecular Forces

Worksheet • 18 Questions

Q1:

The boiling points of the hydrogen halides increases in the order H C l < H B r < H I < H F .

Which interactions are responsible for the difference between the boiling points of H C l and H F ?

  • AHydrogen bonds
  • BIon-dipole attractions
  • CDispersion forces
  • DIonic bonds
  • EDipole-dipole attractions

Which interactions are responsible for the difference between the boiling points of H C l and H B r ?

  • ADispersion forces
  • BIon-dipole attractions
  • CHydrogen bonds
  • DIonic bonds
  • EDipole-dipole attractions

Q2:

In which of the following sequences are the compounds arranged in order of increasing boiling point?

  • A S i H < H C l < H O 4 2
  • B H O < H C l < S i H 2 4
  • C S i H < H O < H C l 4 2
  • D H C l < H O < S i H 2 4
  • E H C l < S i H < H O 4 2

Q3:

The boiling point of ethanoic acid is greater than that of 1-propanol. Which interactions are mainly responsible for this difference?

  • AHydrogen bonds
  • BIon-dipole attractions
  • CDispersion forces
  • DIonic bonds
  • EDipole-dipole attractions

Q4:

For which of the following pairs of compounds is the difference in melting point mostly due to differences in the strength of hydrogen bonding?

  • A 𝑛 -Butane and 1-butanol
  • B1-Chloropropane and 2-chloropropane
  • C 𝑛 -Hexane and cyclohexane
  • DDichloromethane and chloroflorm
  • ELithium hydride and sodium hydride

Q5:

What happens to the surface tension and viscosity of water with increasing temperature?

  • AViscosity and surface tension both decrease.
  • BViscosity and surface tension are both constant.
  • CViscosity and surface tension both increase.
  • DViscosity decreases and surface tension increases.
  • EViscosity increases and surface tension decreases.

Q6:

In which of the following sequences are the compounds arranged in order of increasing boiling point?

  • A F < C l < B r 2 2 2
  • B C l < F < B r 2 2 2
  • C B r < C l < F 2 2 2
  • D F < B r < C l 2 2 2
  • E C l < B r < F 2 2 2

Q7:

The density of liquid diethyl ether at standard temperature and pressure is 0.713 g/cm3. The density of gaseous diethyl ether vapor under the same conditions is 0.003 g/cm3. Which interactions are mainly responsible for the difference between the densities of the two phases?

  • ADispersion forces
  • BIon-dipole attractions
  • CHydrogen bonds
  • DIonic bonds
  • EDipole-dipole attractions

Q8:

Vegetable oil is immiscible with water. Based on the intermolecular interactions, why is this?

  • AThe water-oil interactions are weaker than the sum of the water-water and oil-oil interactions.
  • BThe formation of an oil layer at the surface of the liquid is favorable, as the surface energy of oil is lower than that of water.
  • CMolecules of oil pack more efficiently with each other, as they are much larger in size than molecules of water.
  • DMixing of oil and water is entropically unfavorable, as water molecules must form highly ordered shells around dissolved oil molecules.
  • EWater only dissolves ionic substances.

Q9:

How does increasing the strength of intermolecular forces typically affect the surface tension and vapor pressure of a liquid?

  • ASurface tension increases and vapor pressure decreases.
  • BBoth quantities remain constant.
  • CBoth quantities increase.
  • DBoth quantities decrease.
  • ESurface tension decreases and vapor pressure increases.

Q10:

Two diatomic molecules interact via dispersion forces. In general, which of the following quantities could be increased to increase the strength of the dispersion forces?

  • AAtomic size
  • BBond energy
  • CMolecular charge
  • DTemperature
  • EBond polarity

Q11:

Which of the following noble gases has the highest boiling point?

  • A X e
  • B K r
  • C H e
  • D A r
  • E N e

Q12:

The density of liquid phosphine ( P H ) 3 at 9 0 C and a pressure of 1 bar is 0.746 g/cm3. The density of gaseous diethyl ether vapor under the same conditions is 0.002 g/cm3. Which interactions are mainly responsible for the difference between the densities of the two phases?

  • AHydrogen bonds
  • BIon-dipole attractions
  • CDispersion forces
  • DIonic bonds
  • EDipole-dipole attractions

Q13:

In which of the following sequences are the compounds arranged in order of increasing boiling point?

  • A S i H < P H < H S 4 3 2
  • B P H < H S < S i H 3 2 4
  • C H S < P H < S i H 2 3 4
  • D P H < S i H < H S 3 4 2
  • E S i H < H S < P H 4 2 3

Q14:

Why is the enthalpy of vaporization of ethane higher than that of methane?

  • AThe ethane molecule has a larger area to interact with neighboring molecules via dispersion forces.
  • BThe lower symmetry of the ethane molecule destabilizes molecular clusters removed from the liquid surface during vaporization.
  • CThe ethane molecule has a larger dipole moment so it interacts more strongly with neighboring molecules via dipole–dipole attractions.
  • DThe more elongated shape of the ethane molecule allows for more densely packed molecular arrangements.
  • EThe ethane molecule has a larger area to interact with neighboring molecules via hydrogen bonding.

Q15:

Which of the following molecules forms the strongest hydrogen bonds?

  • A H F
  • B H 2
  • C H C l
  • D H I
  • E H B r

Q16:

Which of the following properties of a liquid solution is not a consequence of evaporation?

  • AThe liquid rises in a capillary tube.
  • BSolute crystals form on the side of the container above the liquid surface.
  • CThe liquid has a detectable smell.
  • DDroplets form on the side of the container above the liquid surface.
  • EThe liquid volume in an open container decreases over time.

Q17:

Why does the viscosity of a liquid decrease with heating?

  • AIntermolecular bonds are weakened.
  • BIntramolecular bonds vibrate more rapidly.
  • CThe conformations of molecules become more linear.
  • DIntramolecular bonds are weakened.
  • EThe vapor pressure of the liquid increases.

Q18:

In which of the following sequences are the compounds arranged in order of increasing boiling point?

  • A C H < C H < C H 4 2 6 3 8
  • B C H < C H < C H 2 6 4 3 8
  • C C H < C H < C H 3 8 2 6 4
  • D C H < C H < C H 3 8 4 2 6
  • E C H < C H < C H 4 3 8 2 6
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