Physical & Molecular Properties of Water

Study Notes

Polarity

Water's polarity is its most important characteristic, giving it its other properties and behaviors.
Polarity results from the bent shape of the water molecule and the uneven distribution of electrons.
This creates a molecule with positively and negatively charged sides.

Universal Solvent

Water is a universal solvent due to its polarity.
It can dissolve many ionic and polar covalent substances, such as salts, minerals, sugars, and alcohols.

Hydrogen Bonding

Hydrogen bonding is a force resulting from the attraction between the positively charged region on one water molecule and the negatively charged region on another adjacent molecule.
Hydrogen bonding results in cohesion (water being attracted to other water molecules) and adhesion (water being attracted to other polar molecules).
Cohesion creates surface tension, making water somewhat viscous and resistant to flowing.
Adhesion allows for capillary action, enabling water to flow in narrow spaces without external forces.

Specific Heat Capacity

The specific heat capacity of a substance is the amount of heat energy required to change its temperature by 1 degree Celsius.
Water has a high specific heat capacity due to hydrogen bonding, requiring a lot of energy to overcome these bonds and change temperature.
When water molecules gain energy, they speed up and hydrogen bonds break; when they lose energy, they slow down and hydrogen bonds form.

Thermal Conductivity

Water has good thermal conductivity due to its molecular structure and hydrogen bonding.
Hydrogen bonds create a network that enables efficient thermal energy transfer between molecules.
The small size and polarity of water molecules also facilitate energy exchange.
Water's high density and specific heat capacity contribute to its ability to absorb and transfer heat.

Density and Temperature

Water is most dense at 4°C and becomes less dense as it freezes.
As water cools from higher temperatures, the molecules slow down and come closer together, increasing the density.
At 4°C, the molecules are most densely packed.
Below 4°C, the molecules begin to form a hexagonal lattice structure due to hydrogen bonding, making ice less dense than liquid water.
This is why ice floats on top of liquid water.

Polarity

Water's polarity is its most important characteristic, giving it its other properties and behaviors.
Polarity results from the bent shape of the water molecule and the uneven distribution of electrons.
This creates a molecule with positively and negatively charged sides.

Universal Solvent

Water is a universal solvent due to its polarity.
It can dissolve many ionic and polar covalent substances, such as salts, minerals, sugars, and alcohols.

Hydrogen Bonding

Hydrogen bonding is a force resulting from the attraction between the positively charged region on one water molecule and the negatively charged region on another adjacent molecule.
Hydrogen bonding results in cohesion (water being attracted to other water molecules) and adhesion (water being attracted to other polar molecules).
Cohesion creates surface tension, making water somewhat viscous and resistant to flowing.
Adhesion allows for capillary action, enabling water to flow in narrow spaces without external forces.

Specific Heat Capacity

The specific heat capacity of a substance is the amount of heat energy required to change its temperature by 1 degree Celsius.
Water has a high specific heat capacity due to hydrogen bonding, requiring a lot of energy to overcome these bonds and change temperature.
When water molecules gain energy, they speed up and hydrogen bonds break; when they lose energy, they slow down and hydrogen bonds form.

Thermal Conductivity

Water has good thermal conductivity due to its molecular structure and hydrogen bonding.
Hydrogen bonds create a network that enables efficient thermal energy transfer between molecules.
The small size and polarity of water molecules also facilitate energy exchange.
Water's high density and specific heat capacity contribute to its ability to absorb and transfer heat.

Density and Temperature

Water is most dense at 4°C and becomes less dense as it freezes.
As water cools from higher temperatures, the molecules slow down and come closer together, increasing the density.
At 4°C, the molecules are most densely packed.
Below 4°C, the molecules begin to form a hexagonal lattice structure due to hydrogen bonding, making ice less dense than liquid water.
This is why ice floats on top of liquid water.

Description

Explore the unique properties of water, including its shape and polarity, ability to form hydrogen bonds, and high specific heat capacity. Learn how these properties make water a universal solvent and good conductor.