Hydrogen Bonding Flashcards
What is a hydrogen bond?
A special type of permanent dipole-dipole interaction found between certain molecules.
What do molecules have to have in order to have hydrogen bonding?
An electronegative atom, with a lone pair of electrons.
A hydrogen atom attached to an electronegative atom.
What does the hydrogen bond act between?
The lone pair of electrons on an electronegative atom and in one molecule and the hydrogen atom in a different molecule.
What is the strongest type of intermolecular attraction?
Hydrogen bonding
How is a hydrogen bond represented in displayed formulae?
As a dashed line.
What is the shape around the hydrogen atom involved in the hydrogen bond?
It is linear.
What type of molecule does hydrogen bonding have an significant on?
Water molecules.
Why is ice less dense than liquid?
Hydrogen bonds hold water molecules apart in an open lattice structure.
The water molecules are further away in ice than in water.
What is a benefit of ice being less dense than water?
It floats which provides an insulating layer for fish.
How many hydrogen bonds can one water molecule form?
4
Why can water molecules form 4 hydrogen bonds each?
There are two lone pairs on the oxygen atom and two hydrogen atoms. As there are two lone pairs of electrons, the oxygen can form two hydrogen bonds.
Why does water form an open tetrahedral lattice with holes?
The hydrogen bonds extend outwards.
What is the bond angle about the hydrogen that is involved in the hydrogen bond?
180 degrees
Why does water have a relatively high melting and boiling point?
It has London forces and hydrogen bonds so lots of energy is needed to overcome the hydrogen bonds.
What happens when the ice lattice breaks?
The rigid arrangement of hydrogen bonds is broken.
