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Melting point and boiling point

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Melting Point and Boiling Point
What is the Melting Point?
The melting point is usually defined as the point at which materials changes from a
solid to a liquid.
The temperature at which solid changes its state to liquid at atmospheric pressure is called the
melting point of that liquid. This is the point at which both liquid and solid phase exists at
equilibrium. The melting point of the substance also varies with pressure and is specified at
standard pressure.
The term ‘freezing point’ is used to denote the temperature at which a liquid
is converted into a solid and can, therefore, be viewed as the opposite of
the term ‘melting point’. However, substances can be cooled below
their freezing points without the formation of a solid. Such liquids are
known as supercooled liquids.
Melting Point and Boiling Point
What is Boiling Point?
The boiling point of a liquid is the temperature at which the vapour
pressure of the liquid becomes equal to the atmospheric pressure of the
liquid’s environment. At this temperature, the liquid is converted into a
vapour.
The boiling point of the liquid depends upon the pressure of the
surrounding. When the liquid is at high pressure, it has a higher boiling point

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than the boiling point at normal atmospheric pressure. The boiling point of
different liquids is different for a given pressure. In 1982, IUPAC defined
the standard boiling point of a liquid as the temperature at which the liquid
boils under a pressure of 1 bar.
Boiling Point Definition
The temperature at which liquid vapour pressure equals atmospheric
pressure is referred to as boiling point. The boiling point is defined as the
temperature at which a liquid’s saturated vapour pressure equals the
atmospheric pressure surrounding it.
The boiling point for any material is the temperature point at which the
material transforms into the gas phase in the liquid phase. This happens
at 100 degrees centigrade for water. The Celsius scale was in fact created
on the basis of the ice/water melting point and the liquid water/vapor
boiling point. Each substance carries its own boiling point.
The boiling point of a substance is dependent on the pressure of its
surroundings. In mountainous terrains (where the altitude is high), the
pressure of the atmosphere is relatively lower than the atmospheric
pressure at sea level. This is the reason why food cooks at a slower pace
in mountainous areas (the lower atmospheric pressure causes water to
boil at temperatures below 100oC).
When all the particles in the liquid phase have been transformed into the
gas phase, the temperature begins to rise again, as long as heat is still
being applied to the surrounding system. As the temperature starts to
increase, so does the particle’s kinetic energy.
Boiling Point of Water
Water can boil, raise temperature or decrease air pressure, in two ways. At
sea level, it is the pressure of air that causes water to boil at 100oC. Water
can boil at a much lower temperature in vacuum, where there’s no air.
That is, if not for the skin that keeps the blood pressurized, body
temperature would be sufficient to cause the blood to boil with water. At
low air pressure the water boils significantly below 100oC at
temperatures.
The boiling point of water is the temperature at which the liquid water
vapor pressure is equal to the pressure surrounding the body, and the
body transforms into a vapour. The boiling point is the temperature for a
particular liquid to boil at. For example, the boiling point for water, at a

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Melting Point and Boiling Point What is the Melting Point? The melting point is usually defined as the point at which materials changes from a solid to a liquid. The temperature at which solid changes its state to liquid at atmospheric pressure is called the melting point of that liquid. This is the point at which both liquid and solid phase exists at equilibrium. The melting point of the substance also varies with pressure and is specified at standard pressure. The term ‘freezing point’ is used to denote the temperature at which a liquid is converted into a solid and can, therefore, be viewed as the opposite of the term ‘melting point’. However, substances can be cooled below their freezing points without the formation of a solid. Such liquids are known as supercooled liquids. Melting Point and Boiling Point What is Boiling Point? The boiling point of a liquid is the temperature at which the vapour pressure of the liquid becomes equal to the atmospheric pressure of the liquid’s environment. At this temperature, the liquid is converted into a vapour. The boiling point of the liquid depends upon the pressure of the surrounding. When the liquid is at high pressure, it has a higher boiling point than the boiling point at normal atmospheric pressure. The boiling point of different liquids is different for a given pressure. In 1982, IUPAC defined the standard boiling point of a liquid as the temperature at which the liquid boils under a pressure of 1 bar. Boiling ...
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