Properties of Water

Water is the most plentiful compound on the surface of the earth, covering 70% of the planet.

In nature, water can be found in liquid, solid, and gas forms.

It is a tasteless and odorless liquid that is almost colorless but has a slight blue tint.

Many substances dissolve in water, which is why it is often called the universal solvent.

Water has several other unique physical and chemical properties, which include:

SPECIFIC HEAT:

Water has a high specific heat, which is the amount of energy needed to change the temperature of a substance.

Due to its high specific heat, water can absorb a lot of heat before it starts to get hot.

This also means that water releases heat energy slowly when it cools down.

PH:

In its pure form, water has a neutral pH.

This means that pure water is neither acidic nor basic.

The pH of water changes when different substances are dissolved in it.

CONDUCTION:

Water is better at conducting heat than any other liquid, except for mercury.

SOLVENT:

Water is known as the universal solvent because it can dissolve a wide variety of chemical compounds. This ability allows water to transport nutrients in runoff, infiltration, and throughout water flow.

SURFACE TENSION:

Water has a high surface tension, which helps form droplets and waves. This property also enables plants to transport water from their roots to their leaves and allows blood to flow through tiny vessels.

DENSITY:

The density of solid water (ice) is lower than that of liquid water, which is why ice floats.

CHEMICAL PROPERTIES OF WATER

➢ HYDROGEN BONDING:

Water is a polar molecule, meaning it has a slight positive charge on the hydrogen side and a slight negative charge on the oxygen side. The bond formed between the positive hydrogen sides of this molecule is known as a hydrogen bond.

Molecules and ions that create water establish hydrogen bonds and are considered hydrophilic.

On the flip side, ions and molecules that do not create hydrogen bonds with water are termed hydrophobic.

LIQUIDITY AT ROOM TEMPERATURE:

At room temperature, most low molecular weight compounds turn into gas when mixed with water. However, hydrogen bonding is what keeps water in its liquid state at this temperature.

CHEMICAL REACTION:

When ionic compounds like NaCl are introduced to water, the hydrogen bonds tend to separate those ionic compounds. This property makes water a natural solvent. Once the ionic compounds dissolve, their anions and cations move freely in the water, enabling further reactions to take place. Therefore, water also aids in chemical reactions.

STABLE TEMPERATURE:

Water requires more heat to increase its temperature compared to other common substances. Since a lot of that heat is used to break the hydrogen bonds, water also holds onto heat, causing its temperature to decrease slowly.

FREEZING POINT:

At 32 degrees Fahrenheit or 0 degrees Celsius and lower, water molecules form hydrogen bonds that create a crystalline lattice structure.

The bonding space in the molecule is a bit more spread out than normal, which causes water to expand when it freezes. This makes ice less dense than liquid water, which is why ice floats.

OTHER PROPERTIES OF WATER

➢ ELECTRICAL PROPERTIES:

Pure water conducts electricity well, but it’s not a perfect insulator because it always has ions from self-dissociation. When an electric current passes through, it causes electrolysis, producing oxygen at the anode and hydrogen at the cathode.

The electrical conductivity of water changes with temperature. As the temperature rises, the electrical conductivity of water increases. For every 1 degree Celsius increase in temperature, the conductivity goes up by 2-3%.

MAGNETIC PROPERTIES:

Liquid water responds to magnetic fields, which can help purify it. Water is diamagnetic and can be levitated in very strong magnetic fields. The magnetic susceptibility of water shifts from negative to positive with changes in magnetic frequency and is reported to be positive.

State of water at different temperatures:

• 0°C or 32°F – Ice or freezing point

• 25°C or 77°F – dynamic equilibrium between liquid and gases

• 100 °C or 212 °F - Steam