1.1 Structure of Water and Hydrogen Bonding

• A water molecule is composed of two hydrogen atoms covalently bonded to a single oxygen atom.
• Hydrogen bonds are stronger than covalent bonds.

  False
• Water's polarity arises because oxygen is more electronegative than hydrogen.
• Which atom in a water molecule has a partially positive charge?

  Hydrogen
• Hydrogen bonding occurs when a hydrogen atom bonded to a highly electronegative atom is attracted to a partially negative atom of another molecule.
• Oxygen is more electronegative than hydrogen
• What allows some objects to float on water?

  High surface tension
• Cohesion refers to the attraction between water molecules.

  True
• The partially positive hydrogen of one water molecule is attracted to the partially negative oxygen
• Hydrogen bonding is an intermolecular attraction in water.


  True
• The hydrogen atoms in a water molecule have a partially positive charge
• The oxygen atom in water has a partially negative charge
• Hydrogen bonding occurs between the partially positive hydrogen of one water molecule and the partially negative oxygen of another.

  True
• What are some biological significances of water's polarity and hydrogen bonding?

  Dissolving polar substances
• What is the biological significance of hydrogen bonding in DNA?

  Maintains double helix structure
• Water's unique properties due to hydrogen bonding are crucial for protein folding
• Hydrogen bonding allows biomolecules to dissolve in the polar water environment of cells.

  True
• What is the shape of a water molecule?

  Bent, V-shaped
• What type of charge does the oxygen atom in a water molecule have?

  Partially negative
• Why is water considered a polar molecule?

  Unequal electron sharing
• The polarity of water allows it to dissolve nonpolar compounds.

  False
• What is hydrogen bonding classified as?

  Intermolecular force
• What type of force is hydrogen bonding?

  Intermolecular force
• Hydrogen bonding occurs between partially charged regions in adjacent water molecules.


  True
• Hydrogen bonds require significant energy to break, allowing water to absorb large amounts of heat
• Match the properties of a water molecule with their description:

  Structure ↔️ Bent, V-shaped

  Polarity ↔️ Unequal electron sharing

  Hydrogen Bonding ↔️ Intermolecular attraction
• Why is a water molecule considered polar?

  Unequal electron sharing
• What charge does the oxygen atom in a water molecule have?

  Partially negative
• What is the primary cause of water's polarity?

  Electronegativity difference
• Which atom in water has a partially positive charge?

  Hydrogen
• Match the property of water with its description:

  Electronegativity Difference ↔️ Oxygen's higher electronegativity leads to unequal electron sharing

  Polarity ↔️ Formation of partially charged regions in water molecule

  Hydrogen Bonding ↔️ Attraction between partially charged regions in adjacent water molecules
• Hydrogen bonding significantly affects water's high heat capacity
• Oxygen is more electronegative than hydrogen.


  True
• How does hydrogen bonding contribute to protein structure?

  Stabilizes folded 3D structure
• What role does hydrogen bonding play in DNA structure?

  Holds base pairs together