Higher Chemistry Starter Questions - LDFs

What is the cause of London dispersion forces?

• Permanent dipoles

• Temporary uneven distribution of electrons

• Hydrogen bonds

• Ionic attractions

Which of the following substances experiences only London dispersion forces?

• NH₃

• H₂O

• CH₄

• HCl

The strength of London dispersion forces increases with:

• Smaller molecules

• Greater difference in electronegativity

• Increased number of electrons

• Presence of hydrogen atoms

Which of the following would have the weakest London dispersion forces?

• Iodine (I₂)

• Neon (Ne)

• Bromine (Br₂)

• Argon (Ar)

Which of these properties is most affected by the strength of London dispersion forces?

• Colour

• Melting point

• Density

• Acidity

Which of the following noble gases has the highest boiling point due to London dispersion forces?

• Helium

• Neon

• Argon

• Xenon

Which pair of molecules would both exhibit only London dispersion forces?

• H₂ and CH₄

• CO₂ and NH₃

• H₂O and Cl₂

• CH₃Cl and Br₂

Why does iodine (I₂) exist as a solid at room temperature, while fluorine (F₂) is a gas?

• Iodine molecules are polar

• Iodine has stronger hydrogen bonding

• Iodine has stronger London dispersion forces

• Fluorine is more electronegative

Which of the following statements is true about London dispersion forces?

• They occur only in polar molecules

• They are stronger than hydrogen bonds

• They become stronger as the number of electrons increases

• They involve permanent dipole interactions

Which of these molecules would be expected to have the lowest boiling point?

• CH₄

• C₂H₆

• C₃H₈

• C₄H₁₀