Physical & Molecular Properties of 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.

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.