Science / Chemistry / Zeolite: Addition compounds of the type Na2O·Al2O3·n sio2·m H2O, with calcium sometimes replacing or present with the sodium. The sodium in the zeolite exchanges with calcium in water, making zeolites useful for water softening. The porous structure of zeolites also makes them effective molecular sieves used as gas adsorbents and drying agents. Artificial zeolites are used as ion exchange resins.

Lanthanum (La)

Science / Periodic Table of Elements / Lanthanum (La): Atomic number: 57, Atomic mass: 138.91 g.mol -1, Electronegativity: 1.1, Density: 6.18 g.cm-3 at 20°C, Melting point: 826 °C, Boiling point: 0.186 nm, Vanderwaals radius: 0.104 nm (+3), Isotopes: 7, MORE

Water Softener

Science / Chemistry / Water Softener: A material that lowers water hardness when dissolved in water. For example, sodium carbonate ('washing soda') softens water by precipitating Ca2+ ions as caco3. Zeolites soften water by exchanging Ca2 MORE

Molecular Sieve

Science / Chemistry / Molecular Sieve: A material that contains many small cavities interconnected with pores of precisely uniform size. Zeolites are an example. Molecular sieves adsorb molecules that are small enough to pass through their MORE