Sodium

A frequently occurring chemical element is a silvery alkali metal. It is a pure element the only stable isotope o f which is Na.

Symbol                                                      Na
Atomic number                                          11
Atomic weight                                           22.9898
Specific thermal weight at 20°C                0.968 g/cm3
Melting point                                             97.72°C
Boiling point                                              883°C
Melting heat                                             115 kJ/kg
Specific thermal capacity at 20°C             1.20kJ/(kg · K)
Thermal conductivity                                 103kJ/(m · K)
Therm. coefficient for linear expansion      72  10-6/K
Coefficient for linear expansion   

Today, large-scalesodium production takes place by means of fused-salt electrolysis of dry sodium chloride in a so-called Downs cell.

In humid air, sodium develops a cover of consisting of a hydroxide carbonate mixture and reacts with water rather vigorously to form hydroxide solution. It should therefore be stored under petroleum.

Today, sodium is easier to handle as it is available in vacuum packaging with a net weight of 10g, 20g, 50g, and 100g. Sodium is used as a modifier for aluminum-silicone cast alloys.

Additional references:
Modification
Sodium bentonite
Sodium carbonate
Sodium silicate



 

 

 

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