Hydrates Lab Report Essay

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CHE 111 Laboratory 3 Hydrates Introduction Hydrates Water molecules combine with the molecules of certain substances, forming loose chemical combinations called hydrates. An example of a hydrate is MgSO4•7H2O. This formula means 7 water molecules are loosely attached to a magnesium sulfate molecule. Other examples of hydrates are Na2SO4•10H2O and Ba(OH)2•8H2O. When the hydrate is heated, it easily loses water molecules attached and becomes an anhydrous salt. The corresponding chemical reaction for hydrated magnesium sulfate can be written as |MgSO4•7H2O ( MgSO4 + 7H2O |(1) | where MgSO4 is the anhydrous salt. Usually,…show more content…
For example, the reaction |BaCl2•2H2O ( BaCl2 + 2H2O |(2) | is reversible, and if water is added to the anhydrous salt BaCl2, formation of BaCl2•2H2O takes place: |BaCl2 + 2H2O ( BaCl2•2H2O |(3) | The reaction of dehydration of hydrated ferrous sulfate |FeSO4•7H2O ( FeSO4 + 7H2O |(4)…show more content…
The simple addition of water to FeSO4 will not lead to the formation of FeSO4•7H2O. Determination of the number of molecules of water in a hydrate. If you do not know how many molecules of water are in one molecule of hydrate and want to find this out, it can be done by measuring the masses of the hydrate and anhydrous compound formed after the heating. For example, let’s assume that we do not know how many water molecules are attached to BaCl2. Let’s call this number X. Then the structural formula of BaCl2 hydrate can be written as BaCl2•XH2O. The reaction of dehydration is |BaCl2•XH2O ( BaCl2 + XH2O |(5) | According to the stoichiometry of the reaction (5) |[pic] |(6) | Where N1 is the number of moles of BaCl2 formed in the reaction (5) and N2 is the number of moles of water lost in the reaction (5). To find out N1 you need to divide the mass of BaCl2 after the reaction by its molar mass. To find out N2 you have to determine the mass of water produced in the reaction. This mass is the difference between the mass of initial compound (BaCl2•XH2O) and the mass of anhydrous salt (BaCl2). N2 is the ratio of the mass of the water produced in the reaction to the molar mass of

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