Because of it strong H bonds water has an unusually high surface tension (why if you make drops with a pipette they stay as little globules). This creates a "skin-like" effect on the surface of the water, allowing insects like the water skater to "walk" on water.

Because of H bonds ice has an unusually low density compared to water. For ice:

the maximum number of H bonds are operative
molecules are held apart in a tetrahedral arrangement of covalent an H bonds
there is much empty space between molecules
it is a larger volume than he same mass of water
it has a lower density than water

Expansion during freezing of water can burst pipes. Also ice floats on water which is why fish (and actually every species on the planet) don't die.

	Criado por Kirsten Rowland quase 10 anos atrás

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