salt crystals and sugar crystals

Crystallization - This technique is used for obtaining a compound in pure solid form of well-defined geometrically shaped crystals. This process of crystallization can be used for the purification of a compound only when the compound and the impurities present in it di..

Crystals are solid particles bounded by plane surfaces, which make definite angles with each other. This gives a definite geometrical shape to the crystal. These shapes are different for different crystals (Fig.6.13). Crystals of the same substance are ..

This method is used to separate a solid compound in pure and geometrical form. A nearly saturated solution of an impure substance is prepared in a hot solvent. The prepared solution is quickly filtered and the filtrate is then allowed to cool slowly in a china dish. The resulting pure crystal..

Water of crystallisation is a definite molecular proportion of water molecules, chemically combined to a salt in the crystalline state. This water of crystallisation is responsible for the geometric shape and colour of the crystals i.e., for the crystalline appearance of a..

Water of Crystallization - When crystals of certain salts are formed, they do so with a definite number of molecules of water, chemically combined in a definite proportion. Water of crystallization is the number of water molecules, chemically combined in a de..

Another type of microphone, widely used in public-address systems, depends for its action on the piezoelectric effect possessed by certain crystals, for example Rochelle salt. The term piezoelectric effect refers to the fact that when pressure is applied on the crystal..

The ionic crystals consist of positively and negatively charged ions arranged in a regular fashion throughout the crystal. They form a network of positive and nagative ions in three dimension in such a way that cations and anions occupy alternate sites. These are held together ..

Certain substances like sodium chloride do not require the help of water to form their crystalline shape. These salts are: i) Chlorides of potassium, sodium and lead. ii) Bromides of potassium, sodium, lead and silver. iii) Iodides of silver and lead. iv) Nitrates of potassium, sodium, l..

Large, well formed crystals can be obtained, by the slow evaporation of a cold and saturated solution of the substance. A large crystal can be grown by suspending a small well formed crystal, in a cold and saturated solution of the substance. The solution must be taken..

When the crystals are unstable, they are gently pressed between the folds of filter papers, and are finally placed in a vacuum desiccator to obtain dry crystals. If the substance is stable and has a high melting point, the crystals are pressed between the fold of the ..