Density of Water, Some Properties of Water, Definition of Density of Water (For CBSE, ICSE, IAS, NET, NRA 2022)

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Density of Water

• Water is a tasteless, transparent, odorless, and colorless chemical substance, which is the main constituent of this planet՚s lakes, oceans, streams, and the fluids of most living organisms.
• Density is the mass per unit volume of a substance.

Some Properties of Water

 Density: 997 kg/ Formula: Molar Mass: 18.01528 g/mol Boiling Point: Melting Point:

Definition of Density of Water

• The density of a material is defined as its mass per unit volume. It՚s a measurement of how tightly matter is packed together.
• It is of a substance can be explained as the relationship between the mass of the substance and volume it takes up.
• Definition: It is the weight of the water per its unit volume, which depends on the temperature of the water.

Factors Affecting Water Density

• There are so many factors which can affect the density of a substance.
• Some factors which affect the density of water is given as below.
• The density of water is approximately around about 1 gram/cubic centimeter (1 g/) .
• It is temperature-dependent, but this relation is said to be non- linear and it is uni modal in nature rather than monotonic.
• When it is cooled from the room temperature, the liquid water tends to become increasingly dense, as with another kind of substances, but approximately at about , pure water is said to reach its maximum density.
• As it gets cooled further, it tends to expand and becomes less dense. This kind of unusual negative thermal expansion is related to strong, intermolecular forces, orientation-dependent, or interactions and it is observed in the form of molten silica.

Density vs Temperature

• Water does not have an absolute density as its density varies with temperature.
• It has a higher density in the liquid state than the solid.
• Check the Density VS Temperature Graph given below to understand how density changes with temperature.

Expression of Density

Density is the ratio of the mass to the volume of a substance:

where ρ = density, units typically or

m = mass, units typically or

V = volume, units typically or

Pure water has its highest density 1000 kg/ or 1.940 slug/ at temperature () .

Specific weight is the ratio of the weight to the volume of a substance:

[2]

where

m = mass, units typically or

g = acceleration due to gravity, units typically and value on Earth usually given as V = volume, units typically

density, units typically

Density of Water at Various Temperature Scales

The water density varies for different temperature. The density (in kg/) of water for different temperature scale (ranging from to ) is given in the table below.

Different Temperature Scale

 Temperature Density in kg/ -30 983.854

Density of Several Liquids with Different Specific Gravities

 Material Density (gram/cm3) Rubbing Alcohol 0.79 Lamp Oil 0.8 Baby Oil 0.83 Water 1.0 Milk 1.03 Liquid Soap 1.06 Corn Syrup 1.33 Maple Syrup 1.37 Honey 1.42

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