VIDEO: Why does water have a high boiling temperature?

This is the chemical structure of water

To understand the relatively high boiling temperature of water, you first need to know how water is made up.

• A water molecule consists of one oxygen atom and two hydrogen atoms.
• Because hydrogen each has one electron and oxygen each has 6 electrons, there are two free electrons on the oxygen atom Electron pairs in front, so that the two hydrogen atom nuclei and the oxygen atom nucleus are not arranged linearly, but the O-H bonds one angle of 104.45 °.
• Due to the higher electronegativity of oxygen, the oxygen atom attracts the electrons of the hydrogen atoms more, so that a dipole is present. Oxygen is partially negatively charged and the hydrogen particles are partially positively charged.
• A water molecule can also split. A hydrogen atom releases one electron completely to the oxygen atom, so that an H⁺-Ion and an OH^--Ion is created. If in one liter of water 10^-7mol H⁺-Ions are present, the water has a pH value of 7.


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• Due to the dipole and the presence of hydrogen atoms, hydrogen bonds form. These also cause the relatively high boiling temperature of water. If this form of bond did not exist, water would be gaseous at room temperature.

Explanation of the high boiling temperature of water

As already mentioned, the reason for the high boiling temperature of water is the occurrence of hydrogen bonds. This is how you can think of hydrogen bonds:

• A water molecule is a dipole. There is a formal negative charge on the oxygen atom and the two hydrogen atoms are positively charged.
• Since the hydrogen atoms are arranged at an angle of approximately 104 ° to the oxygen atom, the negative charge, in the form of the free electron pairs, is easy to reach.
• This allows a positively charged hydrogen atom from a second water molecule to attach itself to the Oxygen atom from the first water molecule attach to it the electrons from the free double bonds attracts. This effect is known as hydrogen bonding.
• Several hydrogen atoms are formally linked to one another through the hydrogen bonds.
• In order to be able to evaporate water, these hydrogen bonds first have to be separated by adding energy. This means that water has a relatively high boiling temperature of 100 ° C.

The density anomaly of the water is also based on the hydrogen bonds.