Gravimetric

RESULTS AND DISCUSSION

The experiment employed the principles ofconstant weighing to quantitatively determine theamount of moisture present in a fertilizer sample.The moisture content of fertilizers is an importantindicator of its quality. The nutrient content orgrade of the fertilizer is dependent on the amountof moisture that it contains. Moreover, there is alegal limitation to the minimum or maximumamount of moisture that a fertilizer can carry. Ifthe moisture content exceeds or falls short of therecommended level, the quality deteriorateswhich may lead to unwanted caking and dustformation.

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 Some materials and solids, such as hydratedcompounds, easily capture water present in theair. Exposure of the objects to air will increasetheir weight as they absorb moisture. Humidityconditions and temperature vary from time totime, such that the sample composition may varyduring different measurements. It is for thisreason that laboratory experiments use constant weighing that involves a cycle of successiveheating using an oven, cooling in a desiccator and weighing using an analytical balance. By this process, the true weight of the object can bedetermined and these values can be duplicated inexperiments that use the same object, and thusminimizing the error due to the presence ofmoisture in the sample.

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 In preparing the fertilizer sample, the fertilizer pellets were ground using a mortar and pestle inorder to increase the surface area of the sample,thereby releasing occluded water and exposingthe adsorbed water, becoming easily vaporizedduring oven-drying.The ground pellets were transferred into a vialand the contents of the vial were transferred to thecrucible to obtain three grams of the fertilizersample using the principle of weighing bydifference. This method is statistically preferred because of smaller error propagation duringweighing. Deviations from the true weight due tospilling the sample inside the balance is prevented because all transfers between...