Hydrogen bonding

Question 1

In a water molecule, both…

Answer 1

the oxygen and
hydrogen atoms attract the shared electrons in
the covalent bond (electronegativity)

Question 2

Oxygen atom is more…

Answer 2

electronegative than the
hydrogen atoms.

• distinct ends with partial charge (polar)

– hydrogen bond

Question 3

Hydrogen bond:

Answer 3

the attractive interaction
between dipoles when the

– positive end of one dipole is a hydrogen atom
bonded to an atom of high electronegativity,
most commonly O or N, and

– the negative end of the other dipole is an atom with
a lone pair of electrons, most commonly O or N

Question 4

The strength of hydrogen bonding is:

Answer 4

approximately 2-5 kcalmol -1
– for water, it is 5 kcalmol-1

Question 5

Water’s polarity and subsequent hydrogen
bonding gives rise to…

Answer 5

unique properties.

– Cohesion and adhesion

– HIGH specific heat and heat of vaporization

– Ice is less dense
– A very versatile solvent (dissolver

Question 6

intermolecular hydrogen bonding result in…

Answer 6

Physical properties of ice and water

Question 7

Hydrogen in polar covalent bonds is…

Answer 7

attracted to nearby electronegative atoms
(O or N)

Question 8

Weak electrostatic bonds

Answer 8

– easily broken

Question 9

Hydrogen bonds are very important in…

Answer 9

biology. Examples:

– properties of water

– protein folding

– DNA and RNA folding

– Temperature regulation