Define base and explain that all alkalies are bases, but all bases are not alkali?

The phase where ice changes directly to gas is called sublimation 

Number of molecules=(12.01+2x15.9994)/112 x na

Answeranything that donates hydrogen ions

A- electron repulsion favors a tetrahedral shape, so the orbitals are 109.5° apart from each other. of a hydrogen atom on methane. they may also contain lone pairs—this explains the geometry of water, which is sp3 hybridized due to the lone pair, which occupies one of the four hybrid orbitals.