The Formation of Alum Crystals from Solutions in Different Thermal Conditions

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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 no
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Figure 1. Alum crystals from Set-up A (left) and Set-up B (right).

Figure 1 shows the crystals formed from the two set-ups. The crystal from set-up A which was formed at room temperature produced relatively larger crystals aggregates compared with the crystal formed at freezer temperature. This shows that temperature is directly proportional to the relative crystal size.

From the two earlier aspects of crystallization discussed, the rate of crystallization and relative crystal size, it can be deduced that they are inversely proportional. Considering set-up A at room temperature, the higher temperature formed crystals at a slower rate, having enough time resulting to the formation of relatively larger crystals.

It is also observable from Figure 1 the relative abundance of the crystals. Set-up A, which is relatively slower in terms of rate of crystallization, has fewer number of crystal aggregates compared to Set-up B. This implies that rate of crystallization is directly proportional to the relative abundance of crystals.

IV. Conclusion
The experiment produced two crystals from super saturated solution of alum in which one is allowed to form at room temperature while the other at freezer temperature. It can be concluded that crystals can be formed from solutions and the crystallization is hasten by the presence of a seed crystal as the basis of the crystal lattice. Both crystals from each of the set-ups were observed to follow the