Table of Contents
The melting point of a substance is the temperature at which it changes from solid-state to liquid. It is sometimes called liquefaction point. When the temperature reaches to melting point of a substance at that point equilibrium exists between liquid and solid state. The melting point of a substance is depending on the Pressure.
For a solid to melts, heat is required to raise its temperature. Heat is then needed to keep the substance in liquid form. Melting points are used to differentiate the compounds into organic and inorganic. It is also used to find out the purity of the substance. The melting point of a pure substance is always higher and has a smaller range than the impure (Mixture).
The temperature at which melting begins is called solidus. While the point where it completes is called liquidus. Eutectics are a special type of mixture that melts at a constant temperature.
The temperature at which the vapor pressure of a substance becomes equals to the surrounding pressure. The boiling point of a substance is depending on the environmental pressure. Liquid in a partial vacuum has a very lower boiling point than the liquid at atmospheric pressure. For example, at sea level water boils at 100 °C but at 1,905 meters (6,250 ft) altitude it boils at 93.4 °C.
The heat of vaporization is the energy required to change a given amount of liquid into gas at a pressure of 1 atm.
Higher the Vapor pressure of a liquid will have a lower boiling point. For example, Methyl chloride has a higher vapor pressure than Butane and it has a lower boiling point than it.
The point at which liquid and its vapor coexist (equilibrium) is called the critical point.
Tungsten and rhenium boiling points exceed 5000 K at standard pressure. While Helium has the lowest boiling point -268.9 °C.
The temperature at which a solid substance changes from a solid-state into liquid at standard pressure.
The melting point of aluminum is 933.47 K ?(660.32 °C, ?1220.58 °F).
Tungsten, or wolfram 3695 K ?(3422 °C, ?6192 °F).
The temperature at which the vapor pressure of a substance becomes equals to the surrounding pressure.
The boiling point of water is 100 °C