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Flashcards in Hydrogen Bonding Deck (6)
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What is hydrogen bonding?

A special type of permanent dipole dipole interaction found between molecules containing O, N, F bonded to a hydrogen atom
Hydrogen bond acts between a lone pair of electrons on ONF and a hydrogen atom


What are the anomalous properties of water?

Solid ice is less dense than liquid water
Water has a relatively high melting and boiling point


Why is ice less dense than water?

Hydrogen bonds hold water molecules apart in an open lattice structure.
The molecules in ice are further apart than in water
Solid ice is less dense than liquid water and floats
When ice melts, the open lattice collapses and molecules move close together


What is the consequence of ice being less dense than water?

Ice floats, forming an insulating layer and prevents the water from freezing over


Why does water have a relatively high melting and boiling point?

Water has London forces and hydrogen bonding.
A large amount of energy is required to break London forces and the hydrogen bonds.
When the ice lattice breaks, the rigid arrangement of hydrogen bonds in ice is broken. When the water boils, the hydrogen bonds break completely.


Other anomalous properties of water.

Relatively high surface tension