Hydrogen Bonds in Water

Introduction to Water's Properties

• Human body is 60-70% water.
• Key to life due to unique chemical properties.
• Cellular metabolism occurs in cytosol.
• Water supports life across cells, organisms, and ecosystems.

Polarity of Water Molecules

• Water molecule: two hydrogen atoms bonded to an oxygen atom.
• Bent molecular structure due to unshared electron pairs on oxygen.
• Electrons in water molecule organize in a tetrahedron.
• Oxygen is more electronegative than hydrogen, creating partial charges.
• Water is a polar molecule due to:
  • Polar covalent bonds
  • Bent shape

Hydrogen Bonding in Water Molecules

• Water molecules attract each other due to polarity.
• Hydrogen bonds form between partial positive hydrogens and electronegative atoms (e.g., oxygen).
• Hydrogen atoms must be attached to electronegative atoms for bonding.

Hydrophilic and Hydrophobic Substances

• Hydrophilic: Substances with charge/polarity that dissolve in water.
• Hydrophobic: Nonpolar substances (e.g., oils, fats) do not dissolve in water and remain separate.

Attribution and References

• Content derived from OpenStax College, Biology, and licensed under CC BY 3.0 and CC BY-NC-SA 4.0.
• Further information can be found in Wikipedia articles on water properties and hydrogen bonds, and in textbooks like "Campbell Biology."