2.2.1 Water

• The oxygen atom in water has a slightly negative charge, while the hydrogen atoms have a slightly positive charge.
• What is the primary reason for the polarity of water molecules?

  Unequal sharing of electrons
• Water molecules can form hydrogen bonds with each other due to their polarity.

  True
• The unequal sharing of electrons in water molecules leads to a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom.
• Which atoms in a water molecule have a slightly positive charge?

  Hydrogen atoms
• Describe the formation of hydrogen bonds between water molecules.

  1️⃣ The hydrogen atoms of one water molecule, which have a slightly positive charge, are attracted to the oxygen atom of a neighboring water molecule, which has a slightly negative charge.

  2️⃣ Hydrogen bonds form between the positive hydrogen atoms and negative oxygen atoms, creating a dipole-dipole attraction.

  3️⃣ This hydrogen bonding creates a unique molecular structure for water, distinguishing it from non-polar molecules.
• The extensive hydrogen bonding between water molecules is responsible for properties such as high boiling point and surface tension.
• Match the property of water with its definition:

  Cohesion ↔️ Attraction between water molecules

  Adhesion ↔️ Attraction between water and other substances
• What is one effect of cohesion in water molecules?

  Surface tension
• What charge does the oxygen atom in a water molecule have?

  Slightly negative
• The polarity of water allows it to form hydrogen bonds with other water molecules.
• Carbon dioxide molecules are polar and can form hydrogen bonds.

  False
• What are two distinctive properties of water due to hydrogen bonding?

  High boiling point and surface tension
• What type of attraction occurs between the positive hydrogen and negative oxygen atoms of neighboring water molecules?

  Hydrogen bonds
• What is the definition of cohesion in water?

  Attraction between water molecules
• What is the definition of adhesion in water?

  Attraction between water and other substances
• What does the high specific heat capacity of water mean?

  Requires much energy to heat
• Match the substance with its specific heat capacity (J/g°C):

  Water ↔️ 4.18

  Ethanol ↔️ 2.44

  Copper ↔️ 0.39
• Ice is denser than liquid water.

  False
• Hydrogen bonding in water molecules is the reason for its high specific heat capacity.


  True
• Water achieves maximum density at 4°C due to the constant breaking and forming of hydrogen bonds.

  True
• The unequal sharing of electrons in water molecules results in a slightly negative charge on the oxygen atom.
• Water's cohesion enables phenomena like surface tension.
• How does the density of ice compared to liquid water help aquatic life?

  Insulates water below
• What is one distinctive property of water resulting from hydrogen bonding?

  High boiling point
• The polarity of water allows it to form hydrogen bonds, creating a unique molecular structure.


  True
• The polarity of water molecules enables them to form hydrogen bonds, influencing properties such as boiling point and surface tension.
• What type of attraction is hydrogen bonding in water molecules?

  Dipole-dipole attraction
• Cohesion and adhesion in water both stem from the hydrogen bonding between water molecules.

  True
• Cohesion in water facilitates the transport of water in plants.
• Adhesion in water allows it to adhere to hydrophilic surfaces due to hydrogen bonds.

  True
• What is responsible for the polarity of water molecules?

  Unequal sharing of electrons
• Water molecules are polar and can form hydrogen bonds.

  True
• Hydrogen bonding in water occurs because the hydrogen atoms have a slightly positive charge and the oxygen atom has a slightly negative charge.
• The extensive hydrogen bonding in water is responsible for its high boiling point and surface tension.


  True
• Cohesion in water results in phenomena such as surface tension.
• Cohesion and adhesion in water play a biological role in water transport in plants.


  True
• Water's high specific heat capacity is due to extensive hydrogen bonding.
• Why is the high specific heat capacity of water biologically significant?

  Regulates temperature in organisms
• What is meant by water's high specific heat capacity?

  Large energy for 1°C