Chemical and physical properties

Lesson 2 : Water, pH and Buffers

Chemical and physical properties

Water has the chemical formula H2O: one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom.

The major chemical and physical properties of water are:

Water is a tasteless, odorless liquid at standard temperature and pressure

  1. Since oxygen has a higher electronegativity than hydrogen, water is a polar molecule. The oxygen has a slight negative charge while the hydrogens have a slight positive charge giving the article a strong effective dipole moment.
  2. The dipolar nature contributes to water molecules' tendency to form hydrogen bonds which cause water's cohesive properties
    • Covalent bonds (electron pair is shared) between oxygen and hydrogen atoms with a bond angle of 104.5o.
    • Oxygen atom is more electronegative that hydrogen atom --> electrons spend more time around oxygen atom than hydrogen atom --> result is a POLAR covalent bond.
    • Creates a permanent dipole in the molecule.
    • Can determine relative solubility of molecules “like dissolves like”.
Last modified: Saturday, 28 January 2012, 7:13 AM