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Chemical Equilibrium

J.R. Chua2 and I.G. Mejarito2
1Department of Mining Engineering, College of Mining Metallurgical and Materials Engineering University of the Philippines, Diliman, Quezon City, Philippines 2Department of Molecular Biology & Biotechnology, College of Science Date Performed: April 22, 2013

Instructor: Julius Victorius A. Saluria

The laws of chemical equilibrium define the direction in which a chemical reaction will proceed, as well as the quantities of reactants and products that will remain after the reaction comes to an end. An understanding of chemical equilibrium and how it can be manipulated is essential for anyone involved in Chemistry and its applications. Iron-Silver Equilibrium

In the first phase of the experiment, iron sulfate was mixed with silver nitrate, and the reaction produced solid silver and iron nitrate, which is formally written as Fe2+ (aq) + Ag+ (aq) ⇄ Ag (s) + Fe3+ (aq)

It has a net equation of:
Fe2+ (aq) + Ag+(aq) ↔ Fe3+(aq) + Ag(s)
The mixture was then placed in a centrifuge in order for the solid silver to settle and separate from the supernate. The supernate was then tested for the presence of Fe2+, Fe3+ and Ag+ by placing K3Fe (CN) 6, KSCN and HCl to 3 separate samples of the supernate. The first result of the test is by adding K3Fe(CN)6, After K3Fe(CN)6 was added to the supernate, a Prussian blue precipitate was formed, more formally written as, Fe2+ (aq) + Fe (CN) 63- (aq) + K+ (aq) → K∙Fe2 (CN) 6 (s) It has a net ionic equation of:

Fe2+(aq) + K3Fe(CN)6(aq) ↔ KFe(III)Fe(II)(CN)6(s) + 2K+(aq) This reaction thus proves that the supernate contains Fe2+.
The second reaction is by adding KSCN, after KSCN was added to the supernate, a blood red complex was formed, more formally written as, Fe(NO3)2 (aq) + 2 KSCN (aq) Fe(SCN)2 (aq) + 2 KNO3 (aq)
It has a net ionic equation of:
Fe3+ (aq) + SCN- (aq) → FeSCN2+ (aq)
The last test was the addition of HCl to the supernate. This produced a...
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