Crystallization 2
DATA AND RESULTS
Substances
Treatment
Observation
Rapid cooling
Slow cooling
Benzoic acid + NaCl + congo red
Heat and filter
Colorless solution,
Coarse crystals
Colorless solution, Fine crystal
Crystallization is a highly effective method for the purification of organic substances, provided that the physical properties of a given compound permits its purification in this manner. Solid organic compounds when isolated from organic mixtures or reactions are seldom pure; they are usually contaminated with small amounts of other compounds called impurities.
Solid purification by crystallization is based upon different solubility in a given solvent. Simplest crystallization process is done by dissolving the impure substances in some suitable solvent at near boiling point. Filtering the hot solution from particles of insoluble materials. Allowing the hot solution to cool thus causing the dissolved substances to crystallize out and separating the crystal from mother liquor.
Solutions contained colored substances must be decolorized. Decolorization is a method used to removed colored substances .Colored impurities can be removed by adding decolorizing carbon such as animal charcoal to the hot solution prior to filtration and the solution is kept hot for a brief period, shaken to wet and filtered. Adsorption occurs very rapidly and no advantage is gained by boiling the suspension for several minutes. It is a mistake to use more decolorizing charcoal than needed, for an excess may absorb some of the substance to be purified and causes losses.
The solution was divided equal and cools as rapid and slow cooling. In slow cooling the crystals formed are larger than the rapid cooling. Substance in slow cooling have more time to formed crystal without disturbing than rapid. The crystals are formed from benzoic acids substance produce coarse and fine crystal separately.
Answer to the results
1. What are the types of crystals? Crystal are classify into
Substances
Treatment
Observation
Rapid cooling
Slow cooling
Benzoic acid + NaCl + congo red
Heat and filter
Colorless solution,
Coarse crystals
Colorless solution, Fine crystal
Crystallization is a highly effective method for the purification of organic substances, provided that the physical properties of a given compound permits its purification in this manner. Solid organic compounds when isolated from organic mixtures or reactions are seldom pure; they are usually contaminated with small amounts of other compounds called impurities.
Solid purification by crystallization is based upon different solubility in a given solvent. Simplest crystallization process is done by dissolving the impure substances in some suitable solvent at near boiling point. Filtering the hot solution from particles of insoluble materials. Allowing the hot solution to cool thus causing the dissolved substances to crystallize out and separating the crystal from mother liquor.
Solutions contained colored substances must be decolorized. Decolorization is a method used to removed colored substances .Colored impurities can be removed by adding decolorizing carbon such as animal charcoal to the hot solution prior to filtration and the solution is kept hot for a brief period, shaken to wet and filtered. Adsorption occurs very rapidly and no advantage is gained by boiling the suspension for several minutes. It is a mistake to use more decolorizing charcoal than needed, for an excess may absorb some of the substance to be purified and causes losses.
The solution was divided equal and cools as rapid and slow cooling. In slow cooling the crystals formed are larger than the rapid cooling. Substance in slow cooling have more time to formed crystal without disturbing than rapid. The crystals are formed from benzoic acids substance produce coarse and fine crystal separately.
Answer to the results
1. What are the types of crystals? Crystal are classify into