# Hydrated Salt Experiment

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Introduction This very experiment is aimed to determine the percent by mass in a hydrated salt (MgSO4•7H2O) in addition to getting acquainted with the equipment in a laboratory. The majority of salts occurring in nature are hydrated (water molecules bonding to the ions of the salt are the part of the structure of the compound). In some salts water molecules bond weakly to the ions and heat makes the salt to by anhydrous. During this experiment we try to identify the percentage of water contained in the hydrated salt by using gravimetric analysis. Materials & Procedure We should measure the mass of a hydrated salt before and after heating to the high temperature. Knowing this mass difference and the mass of the anhydrous salt we are able to calculate the percent of water in the hydrated salt. During this experiment we…show more content…
From the calculations, we can see that the result does not varies significantly in trial 1 and trial 2 (the difference between the results is about 0,5%), which approves that the experiment is done properly with the small extent of error. As we know the formula of Epsom salt, MgSO4•7H2O, we can calculate theoretical value of percent water in this salt. From the periodic table we can obtain molar masses for the elements in MgSO4•7H2O: Mg = 24.31 g/mol, S = 32.07 g/mol, O = 16.00 g/mol, H = 1.008 g/mol The mass of 1 moles of MgSO4•7H2O = 24.31 g/mol + 32.07 g/mol + 11(16.00 g/mol) + 14(1.008 g/mol) = 246.49 g/mol The mass of 7 moles of water = 14(1.008) + 7(16.00) = 126.11 g/mol %H2O = [(126.11 g/mol)/(246.49 g/mol)]*100% =