Advanced Placement (AP) Biology Practice Exam

What characteristic of water allows it to have a high specific heat?

1. Hydrogen bonding

2. Ice formation

3. Ionization

4. Polarity

The correct answer is: Hydrogen bonding

The characteristic of water that allows it to have a high specific heat is hydrogen bonding. In water, molecules are held together by hydrogen bonds, which are relatively strong compared to other types of intermolecular forces. These bonds require a significant amount of energy to break, leading to water's high specific heat capacity. When heat is added to water, much of that energy goes into breaking the hydrogen bonds rather than raising the temperature of the water. This property has important implications for the stability of aquatic environments and the climate, as it helps moderate temperature fluctuations. While the other characteristics, such as polarity, also play a role in water's properties, it is the extensive hydrogen bonding that specifically contributes to its high specific heat. Polarity leads to the formation of hydrogen bonds, but it is the presence and strength of these bonds that mainly dictate how much energy water can absorb before experiencing a temperature change.