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Liquids MCQs for MDCAT Practice

Chemistry section, Liquids chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 584 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    Why is the boiling point of methane greater than that of neon?
    • A molecule of methane has a greater mass than a molecule of neon.
    • A molecule of methane has more electrons than a molecule of neon.
    • Molecules of methane have stronger inter-molecular forces than those of neon. (correct answer)
    • Molecules of methane from hydrogen bonds,but those of neon do not.
    Correct answer: C
    Methane's higher boiling point than neon stems from stronger van der Waals forces due to its larger electron cloud and molecular size.
  2. Question 2
    At the boiling point, added heat is used to break __ forces.
    • Intermolecular (correct answer)
    • Ionic
    • Magnetic
    • Nuclear
    Correct answer: A
    At the boiling point, thermal energy supplied as latent heat of vaporization is utilized exclusively to overcome intermolecular attractions, converting liquid to vapor without breaking chemical bonds.
  3. Question 3
    If a block of ice is being heated, in which of the following stages would all heat energy be utilized in breaking all the hydrogen bonds only?
    • During the melting of ice into water
    • During the heating of steam
    • During the boiling of water (correct answer)
    • During the heating of water
    Correct answer: C
    Phase transitions like boiling involve absorbing heat to break intermolecular forces (hydrogen bonds in water) without temperature change.
  4. Question 4
    Which of the substances listed decreases the freezing point of benzene (C6H6) more than the others if a lab tech tries to dissolve 5.00 grams in 500.0 g of benzene?
    • E. sucrose, C12H22O11
    • paradichlorobenzene, C6H4Cl2
    • sodium chloride,NaCl
    • aluminum chloride, AlCl3 (correct answer)
    Correct answer: D
    Freezing point depression depends on the molality and van't Hoff factor; ionic compounds that dissociate more yield greater depression.
  5. Question 5
    Evaporation is a ____ process.
    • Exothermic
    • Spontaneous (correct answer)
    • Non-Spontaneous
    • None of these options are correct
    Correct answer: B
    Evaporation is a spontaneous process that occurs at the surface of a liquid, driven by the kinetic energy of molecules.
  6. Question 6
    The force of attraction due to temporary dipoles is
    • Dipole-dipole
    • Dispersion force (correct answer)
    • Debye force
    • Ion dipole force
    Correct answer: B
    Temporary dipoles induce temporary attractions between molecules, known as dispersion forces, crucial for nonpolar substances.
  7. Question 7
    To boil water at 110°C, external pressure should be:
    • 200-760 torr
    • 760-1200 torr (correct answer)
    • 665-670 torr
    • 660-700 torr
    Correct answer: B
    Boiling point elevation requires external pressure to exceed atmospheric pressure, correlating with higher temperatures.
  8. Question 8
    Which property of water helps to maintain the integrity of lipid bilayer membranes?
    • Specific heat capacity
    • Hydrogen bonding
    • Cohesion and adhesion
    • Hydrophobic exclusion (correct answer)
    Correct answer: D
    Hydrophobic exclusion, driven by water's polarity, forces nonpolar lipids into the membrane interior, maintaining bilayer integrity.

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Read the full Liquids chapter notes: Liquids notes. Or browse every chapter.