Water Properties

Question 1

Specific Heat Capacity

Answer 1

Water has a high specific heat capacity, requiring a significant amount of energy to change its temperature due to the presence of hydrogen bonds.

The abundance of hydrogen bonds restricts water molecule movement, stabilizing temperatures in aquatic environments and aiding organisms in maintaining stable body temperatures.

Question 2

Latent Heat of Vaporization

Answer 2

Water’s high latent heat of vaporization, attributed to hydrogen bonding, necessitates substantial energy to change its state from liquid to gas.

Water is an excellent coolant (e.g. sweat)
Water is a good medium for metabolic reactions (absorbs heat from exothermic reactions)

Question 3

Molecular Composition

Answer 3

Water (H2O) consists of two hydrogen atoms covalently bonded to one oxygen atom.

The unequal sharing of electrons results in oxygen being more electronegative, leading to polarity.

Water is a polar molecule, with oxygen carrying a slight negative charge and hydrogen atoms carrying slight positive charges.

Question 4

Hydrogen Bonding

Answer 4

Hydrogen bonding occurs when the slightly positive hydrogen atom of one water molecule bonds with the slightly negative oxygen atom of another water molecule.
This bonding is crucial for various properties of water.

Question 5

Cohesion and Surface Tension

Answer 5

Cohesion refers to the attraction between molecules of the same substance.
Water molecules exhibit cohesion due to hydrogen bonding, allowing them to stick together.
An example of cohesion is surface tension, where hydrogen bonds create a strong film on the water’s surface, enabling small insects to walk on water.

Question 6

Adhesion

Answer 6

Adhesion involves the attraction between molecules of different substances.
Water’s polarity causes it to adhere to other polar or charged surfaces.

An example of adhesion is water traveling up the xylem of plants, facilitated by cohesion and adhesion.

Question 7

Density

Answer 7

Water is less dense as a solid than as a liquid (maximum density ~ 4°C)

Ice floats on water (prevents oceans from freezing as ice layer prevents exposure to cold temperatures

Question 8

Solvent

Answer 8

Dipolarity means water can dissolve molecules that are polar or charged

Water is a good transport medium (e.g. the blood system can transport soluble materials in its plasma)