Chem 111 Lab Report - [ Type text] [Type text] Coppa 1 The...

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[Type text] [Type text] Coppa 1 The Chemistry of Natural Waters Lab Report Experiment 10 By: Andrew Coppa April 5, 2011 Chemistry 111 – Section 102 TA: Cole McDonald Group Members: Leah Cooperman, Alex Brown, Yi Chen
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[Type text] [Type text] Coppa 2 Introduction: Water is a vital nutrient that organisms need in order to survive. For example, the human body alone is made up of 60-75% water, i which shows that without water, we could not exist. Because water is so important to the human race as well as other organisms, it is important that we know the hardness of the water we are consuming. However, let it be known that the hardness of water has been said to pose no threat to human health. In fact, the hardness of water may slightly contribute to dietary needs of humans. 3 The threat that hard water poses, is through cleaning, the movement of water through pipes, and scale formation. Scale formation is when rocklike deposits form on pipes, boilers, tubes, and any other surface that may involve an evaporator surface. This occurs because when the water evaporates, it leaves behind the minerals that it was composed of. Because these rocklike deposits pose a threat to pipes and other surfaces by closing them up and blocking them, scale formation is one of the biggest problems in industry today. This means that the harder the water, the more problems are caused within industries since the rocklike deposits can “interfere with heat transfer in boilers, leading to gross energy inefficiencies, and can often lead to metal corrosion and structural weakness”. 2 The hardness of water is essentially determined by the amount of divalent cations within the solution. The two most important chemical species however, are Calcium and Magnesium. Since the hardness increases as the amount of divalent cations increases, we can say that the two are directly proportional. (6) As your concentrations of Calcium and Magnesium increase, so will your hardness. The amount of concentration that there needs to be in the sample for it to be deemed ‘hard’ is 120-180mg/L and higher, while anything less than 17 mg/L is ‘soft’. 3 To determine the hardness of a sample we can either use EDTA or AA, which are the most common
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[Type text] [Type text] Coppa 3 methods. Either of these methods will produce a number corresponding to the amount of Calcium or Magnesium found in the sample. Once we know the number, we can then figure out the parts per million, or PPM, which is another way of describing water’s hardness. (8) EDTA, or ethylenediaminetetraacetic acid, is normally used in a titration method. (5) The EDTA is mixed with the water being tested, along with the indicator Eriochrome Black T (EBT).
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This note was uploaded on 05/04/2011 for the course CHEM 111 taught by Professor Keiser,josephthoheckman,kimberlyproia,michaelantsanders,rebeccalo'neill,ryanshaw during the Spring '07 term at Pennsylvania State University, University Park.

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Chem 111 Lab Report - [ Type text] [Type text] Coppa 1 The...

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