1. Strong Intermolecular Forces:
* Water molecules are polar, with a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom.
* This polarity allows for the formation of hydrogen bonds - strong attractions between the positively charged hydrogen of one water molecule and the negatively charged oxygen of another.
2. Breaking Bonds Requires Energy:
* To boil, water molecules need to overcome these strong hydrogen bonds and escape into the gas phase.
* The energy required to break these bonds is relatively high, contributing to the high boiling point of water (100°C).
3. Comparison with Similar Molecules:
* Consider other molecules with similar molecular weights, like methane (CH4).
* Methane has a much lower boiling point (-161°C) because it lacks hydrogen bonding. It only experiences weaker London dispersion forces.
In summary:
* Hydrogen bonding creates a strong network of intermolecular forces in water, requiring a significant amount of energy to overcome and vaporize.
* This is why water has an unusually high boiling point for a molecule of its size.
Other Effects of Hydrogen Bonding:
* High melting point
* High surface tension
* Excellent solvent properties
