The Formation of Alum Crystals from Solutions in Different Thermal Conditions

961 WordsDec 23, 20124 Pages
The Formation of Alum Crystals from Solutions in Two Different Thermal Conditions Burce P.J., Cachuela J.A.A., Capistrano M.M. I. Objectives The experiment aims to describe crystals and its aggregates by creating crystals of Alum (AlK (SO4)2 ∙12H2O), commonly known as Tawas, from solution. Two setups will be created; crystals from each setup will be allowed to form at two different thermal conditions. With this, the experiment also aims to describe how temperature affects the formation of crystals. II. Methodology First, 2 liters of water was boiled. Two hundred grams of alum was dissolved to the water while constantly stirring. After this, more alum was added to the mixture while constantly stirring until the solution can…show more content…
All the alum added into the mixture was dissolve because of the high temperature during boiling. Upon removing the solution from heat, the solute particles dispersed on the medium starts interacting with each other to crystallize. The process of crystallization was aided by the use of the seed crystal. The seed crystal is a small chunk of alum. It eases the crystallization process by being the basis of crystallization, being the foundation of the crystal lattice. With this, the need for the random molecular collision to form the foundation of the crystal lattice is eliminated. The random solute particles, in this case alum particles, just needs to interact with the seed crystal for the crystal lattice to increase in size. The alum crystals formed from both set-ups exhibits the same shape, octahedron. Steno’s Law of Constancy of Interfacial Angles was followed by the alum crystals; the only difference is the relative crystal size. The law states that the angles between the crystal faces of a given species are constant, whatever the lateral extension of these faces and the origin of the crystal. It also states that these constant angles are specific characteristics of the crystal specie. Temperature affects several aspects of crystallization which was observable from the experiment. The temperature affects the rate of crystal formation. From the experiment, crystals formed immediately in Set-up B

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