what are crystals,crystallisation,its types,shapes&solubility,solute,solvent,saturated&supersaturated solution

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definitions,explanations,pictures,and definition of mother liqour

Answer 1

I hope this helps , scroll down for pictures and definition of mother liqour .Here is an informative article I hope may be of help with a link provided below .Crystals and Crystal Systems
A. Unit Cells
When atoms or molecules are lined up in an orderly arrangement and connected by bonds, and these atoms or molecules have a repeating pattern, we can then say this material is a crystalline substance. The smallest subdivison of a crystal is a unit cell. It is a regular pattern of atoms held together by electrical forces or bonds. These unit cells are far too minute to be seen individually but can be combined together in incredibly large numbers to form visible shapes. As an example of the staggeringly larg e numbers of unit cells we are talking about we can take as an example sodium chloride, table salt. One typical salt grain has about 5.6 x 1018 unit cells. (Each salt unit cell is composed of four atoms of sodium and four atoms of chlorine.)1

B. Crystal Systems
When the unit cells group together they leave no empty spaces between themselves. This results in a limited number of crystal systems that can form. These systems can be grouped as follows:2

1.Isometric or cubic—three edges of equal length and at right angles to one another.
2.Tetragonal—three edges at right angles but only two edges of equal length.
3.Orthorhombic—three edges at right angles but all edges of different lengths.
4.Monoclinic—two edges at right angle, the other angle not; and all edges of different lengths.
5.Triclinic—all three edges of different lengths and all angles not at right angles.
6.Hexagonal—two edges are equal and make angles of 60 to 120 degrees with each other. The third edge is at right angles to them and of different length.
Two activities which can be used with the students are to be found in Appendix 1 listed within Activity 2. The first is a simple introduction to the various crystal shapes by drawing them and identifying their title. The second activity applicable to crys tal shapes using the diagrams given there. In doing so, the student can in very concrete terms understand the variety of angles and lengths involved.

C. Growing Crystals
Once the student has a basic understanding of what a crystal is, he or she is often anxious to create some crystals of his or her own. This provides a natural opportunity to introduce some new terms which they will use in their laboratory experiences.
Since most of their crystals will be formed by solution the student needs to add the words solute, solvent, and solution to his vocabulary. The solute is the substance being dissolved and the solvent is the substance doing the dissolving. A solvent can ho ld in solution just so much of the solute. At this point we say the solution is saturated. If there is less solute in the solution than it would ideally hold we would then say it is an unsaturated solution. And in some cases such as when we heat the solve nt we can continue to add solute and it will dissolve. When the heat source is removed and the solution’s temperature falls the extra solute may remain in solution. This fragile situation is called supersaturation and is the basis for our crystal growth experiments.

Solubility, or the amount of solute which can be dissolved in the solvent, is affected by a number of factors, one of which is the temperature of the solvent. Generally speaking we increase solubility of solid solute when we increase the temperature of the solvent. (This is not true of the solubility of gases in a solvent as is witnessed by anyone who has sipped a glass of warm, flat soda.) In Appendix 2 there are some solubility figures which the student can use to set up graphs of solubility curves.

Crystal growth is a very orderly and regulated process. A crystal grows from the southside with the atoms of the compound being added according to a very specific pattern. If there is not enough space for the crystal to grow unhindered it will increase on ly until it meets something which gets in its way and then stop. Often many small crystals begin forming at the same time, and they grow until their edges meet at varying angles. They do not join to form a single large crystal but rather remain a jumble of small individual crystals forming a polycrystalline mass. The adjoining faces of the crystals are called the grain boundaries. These boundaries are particularly evident in metals which have formed by fairly rapid cooling of the molten form. During the c ooling process innumerable small crystals form and grow until they bump into a neighboring crystal.

Crystals can form from the cooling or evaporation of solutions, or from the cooling of molten solid, or the cooling of vaporized substances. In Appendix 3 you will find a number of experimental techniques for demonstrating crystal growth and for student p articipation in crystal growing.


D. Impurities3
While the regularity and order of crystals have been stressed thus far, it is important to note that this order can be disturbed. Generally the cause is the inclusion of an impurity. Sometimes this is the result of a crystal forming around a foreign parti cle. This can usually be detected by microscopic examination. But other times it is actually an invasion by an atom with approximately the same size and shape as the host crystal, and the pattern is not disrupted. This is called a mixed crystal. The class ic example of this is alum which is composed of potassium sulfate and aluminum sulfate in a one to one proportion. A similar compound is chrome alum, in which you find potassium sulfate combined with chromium sulfate.
Many crystals in nature demonstrate this mixed crystal condition in the replacement of aluminum by chromium or sometimes iron. Rubies are a good example of this, being composed of aluminum oxide with chromium replacing some of the aluminum, and also sapph ires which replace the aluminum with titanium and iron.

In some cases a slightly different atomic substance can enter a crystal but only in small quantities. This is called a substitutional impurity. A most relevant example of this is substitution of phosphorus or boron atoms in silicon crystals. These “impure ” compounds are used to make transistors for electronic instruments.

Sometimes a different kind of impurity enters a crystal. These foreign atoms may be very small compared to the host substance and fit in between the orderly arranged host atoms. If the host substance has a generous size pattern the invading atoms could be as large as the host atoms themselves. The additional atoms are called interstitial impurities. A well known example of this is carbon and iron, which makes steel.

A third kind of defect could be called a vacancy. This results from very rapid crystal growth during which some of the atomic sites are simply not filled. The milky or veiled appearance of home-grown crystals, however, is caused by very large openings called voids. It generally occurs when the evaporation of solvent proceeds too rapidly and incomplete crystallization happens. The white coloration is caused by the presence of a liquid solution that is trapped in the open spaces of the crystal. Vacancies on the other hand are far too small to be visible

The following links provide picture examples of crystals.
#1. http://www.seawhy.com/xlpix.html
#2. http://www.rainbowcrystal.com/crystal/mineralpix.html
#3. link to snow crytal photos and info http://www.its.caltech.edu/~atomic/snowcrystals/

Definition of mother liqour >Sugar beet (Beta vulgaris L.), a member of the Chenopodiaceae subfamily and the Amaranthaceae family, is a plant whose root contains a high concentration of sucrose. ... syrup is called "mother liquor". This is concentrated ... the mother liquor forms around them. The resulting sugar crystal .

Answer 2

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