Properties of water (polarity, cohesion, adhesion, heat capacity) Knowledge-Based Download PDF

Questions

1. 1.

   How does the high specific heat capacity of water directly benefit living organisms and their ecosystems?

   • A) It facilitates the rapid dissolution of nonpolar lipids and hydrocarbon waxes within cellular membranes.
   • B) It stabilizes internal cellular temperatures and buffers aquatic habitats against rapid thermal fluctuations.
   • C) It accelerates the spontaneous ionization of neutral water molecules to drive oxidative phosphorylation.
   • D) It permits water molecules to readily break their intramolecular covalent bonds under mild environmental conditions.
2. 2.

   What property of water allows lightweight insects, such as water striders, to stand and glide across the surface of a pond without sinking?

   • A) High surface tension produced by cohesive forces between water molecules
   • B) Strong adhesive interactions between water and the insect's hydrophobic cuticle
   • C) High specific heat capacity preventing local temperature fluctuations
   • D) Lower density of surface water relative to deeper liquid layers
3. 3.

   In a water molecule, the oxygen atom is significantly more electronegative than the hydrogen atoms, causing the shared electrons to spend more time closer to the oxygen nucleus. What direct consequence does this unequal electron distribution have on the water molecule?

   • A) It gives the entire water molecule a net positive electrical charge.
   • B) It converts the intramolecular links into nonpolar covalent bonds.
   • C) It produces partial negative and positive regions, establishing molecular polarity.
   • D) It prevents the molecule from engaging in electrostatic attractions with neighboring molecules.
4. 4.

   The upward transport of water in the xylem vessels of vascular plants relies on water molecules sticking to one another while also clinging to the hydrophilic walls of the vessels. Which properties of water are directly responsible for these respective interactions?

   • A) Cohesion and adhesion
   • B) Adhesion and cohesion
   • C) Capillary action and high heat of vaporization
   • D) Surface tension and high specific heat capacity
5. 5.

   Water has a remarkably high specific heat capacity compared to most other liquids of similar molecular weight. Which molecular mechanism is primarily responsible for this property?

   • A) A large amount of thermal energy is absorbed to disrupt hydrogen bonds between water molecules before their kinetic energy can increase.
   • B) Strong covalent bonds between oxygen and hydrogen atoms within each water molecule must be broken before temperature can rise.
   • C) Rapid dissociation of water molecules into hydronium and hydroxide ions neutralizes incoming thermal energy.
   • D) Nonpolar interactions between adjacent water molecules create an inflexible matrix that resists thermal motion.