Amorphous silica has a density of about 2.2 g/cm3, whereas the density of crystalline quartz is 2.65 g/cm3. account for this difference in densities

Silica occurs in both amorphous as well as crystalline forms.

Amorphous silica are those in which the silica atoms are not arranged in a defined repeating pattern. This lacks the proper arrangement and tightening of crystals or atoms.

Whereas, crystalline quartz are those in which the silica atoms are arranged in a repeating pattern, forming a definite structure. Here the crystals are tightly arranged.

Due to the differences between their crystal arrangement and structure, the density of crystalline quartz is higher than the density of amorphous silica.

- measure reactants precisely. ( first choice)

- stir to the reaction take place. ( second choice)

- wait patiently until the reaction completes. ( fourth choice)

- make sure to recover as much copper as possible. ( last choice)