AP BIOLOGY

BIOCHEMISTRY

POLAR AND NONPOLAR MOLECULES

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Water has a high boiling and melting point because
A
it’s a heavy molecule
B
strong intermolecular forces
C
the molecules do not stick together very well
D
water is a super solvent
Explanation: 

Detailed explanation-1: -Water has a high boiling point because its molecules are bound together by hydrogen bonding, which is a very strong intermolecular force. It takes more kinetic energy, or a higher temperature, to break the hydrogen bonding between water molecules, thus allowing them to escape as steam.

Detailed explanation-2: -Because intermolecular forces increase the bonding strength between two or more molecules, intermolecular forces can impact the melting and boiling points of compounds. In general, as intermolecular force strength increases, the melting and boiling points of a substance also increase.

Detailed explanation-3: -Water molecules in liquid state have the ability to form hydrogen bonds with each other. These hydrogen bonds are some of the strongest of all intermolecular forces, so a large amount of energy is needed to break these interactions − this is the main reason why water has such a high relative boiling point.

Detailed explanation-4: -The overarching principle involved is simple: the stronger the noncovalent interactions between molecules, the more energy that is required, in the form of heat, to break them apart. Higher melting and boiling points signify stronger noncovalent intermolecular forces.

Detailed explanation-5: -All of the same principles apply: stronger intermolecular interactions result in a higher melting point. Ionic compounds, as expected, usually have very high melting points due to the strength of ion-ion interactions (there are some ionic compounds, however, that are liquids at room temperature).

There is 1 question to complete.