Flashcards in Hydrogen bonding Deck (4)
What are Hydrogen bonds?
- Special type of permanent dipole-dipole interaction found between molecules containing a strongly electronegative atom with lone pairs (like oxygen, fluorine and nitrogen) and hydrogen atoms
- Hydrogen bond acts between a lone pair on a EN atom in one molecule and a hydrogen atom in a different molecule
Why is water perfect for hydrogen bonding?
- Unlike others it has 2 lone pairs AND two hydrogens so it is not limited by anything.
* Due to H.Bonding water has anomalous properties
Why is the ice less dense than water?
- Hydrogen bonds hold water molecules apart in an open lattice structure
- The water molecules in ice are further apart than in water. This is because water can form 4 hydrogen bonds and when all are formed, it makes the bond extend outwards which holds water molecules slightly apart as a tetrahedral lattice full of holes.
- Solid ice is less dense than liquid water and it floats. The holes in the open lattice structure collapses and molecules move closer making water more dense.