Water is a transparent and nearly colorless substance composed of the chemical elements hydrogen and oxygen, that are connected by covalent bonds. On Earth, water exists in gaseous (steam or water vapor), liquid, and solid states (ice). It is one of the most plentiful and essential of compounds and it is the main constituent of Earth’s streams, lakes, and oceans, and the fluids of most living organisms. It is vital for all known forms of life.
|Ultimate Tensile Strength||N/A|
|Young’s Modulus of Elasticity||N/A|
|Melting Point||0 °C|
|Thermal Conductivity||0.598 W/mK|
|Heat Capacity||4200 J/g K|
Composition of Water
Chemically pure water (H2O) contains two elements – hydrogen and oxygen. But in nature such water does not exist and always contains various substances from the air or surface, such as CO2.
Applications of Water
Water is necessary for human survival. But it is used in industry, agriculture, chemistry and energy production. In nuclear engineering is water using as a reactor coolant, a moderator or a neutron shielding.
Thermal Properties of Water
Water – Melting Point
Melting point of Water is 0 °C.
Note that, these points are associated with the standard atmospheric pressure. In general, melting is a phase change of a substance from the solid to the liquid phase. The melting point of a substance is the temperature at which this phase change occurs. The melting point also defines a condition in which the solid and liquid can exist in equilibrium. For various chemical compounds and alloys, it is difficult to define the melting point, since they are usually a mixture of various chemical elements.
Water – Thermal Conductivity
Thermal conductivity of Water is 0.598 W/(m·K).
The heat transfer characteristics of a solid material are measured by a property called the thermal conductivity, k (or λ), measured in W/m.K. It is a measure of a substance’s ability to transfer heat through a material by conduction. Note that Fourier’s law applies for all matter, regardless of its state (solid, liquid, or gas), therefore, it is also defined for liquids and gases.
The thermal conductivity of most liquids and solids varies with temperature. For vapors, it also depends upon pressure. In general:
Most materials are very nearly homogeneous, therefore we can usually write k = k (T). Similar definitions are associated with thermal conductivities in the y- and z-directions (ky, kz), but for an isotropic material the thermal conductivity is independent of the direction of transfer, kx = ky = kz = k.
Water – Specific Heat
Specific heat of Water is 4200 J/g K.
Specific heat, or specific heat capacity, is a property related to internal energy that is very important in thermodynamics. The intensive properties cv and cp are defined for pure, simple compressible substances as partial derivatives of the internal energy u(T, v) and enthalpy h(T, p), respectively:
where the subscripts v and p denote the variables held fixed during differentiation. The properties cv and cp are referred to as specific heats (or heat capacities) because under certain special conditions they relate the temperature change of a system to the amount of energy added by heat transfer. Their SI units are J/kg K or J/mol K.
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