Water Chemistry - Essay Example

Water Chemistry Affiliation Solutions Polysaccharide- these are polymers that are made of several chains of either monosaccharide units or disaccharide units Glucose- this is an example of a monosaccharide. It is a simple sugar consisting of a hydroxyl group (OH) in the structure. Glucose structure Amino acids- organic compounds with an amino group (NH2) and a carboxyl group (COOH). Fats- organic compounds with carbon, hydrogen and oxygen present in their structure. Fats contain glycerol which houses hydroxyl (OH) group and fatty acids which houses carboxyl (COOH) group.

Proteins- Contain carbon, hydrogen and oxygen in their structure. Proteins consist of both amine (NH2) and carboxyl (COOH) groups. #2 Solutions (a) Entropy- this is a measure of how much a system is disordered. Denoted by S. (b) Enthalpy- this is the product of pressure of a system and volume of a system added to the internal energy of a system. (c) Gibbs Free Energy- this is the product of entropy and absolute temperature subtracted from the enthalpy of a system. (d) Exothermic reaction- this is a chemical reaction in which energy is released in the form of either light or heat.

Endothermic reaction- this is a chemical reaction where energy is absorbed from the surrounding. The energy can be in form of heat but not in all cases. #3 Solutions (a) Calculate the enthalpy reaction for Reactions are: Simplifying the three equations: (b) Calculate the Gibbs free energy of the following reaction = -32.8kcal/mole = - 94.3kcal/mole = - 71.7kcal/mole = - 56.6kcal/mole (g)= - 88.5kcal/mole ΣnHfproducts - ΣnHfreactants = {(-32.8) + (-88.5)}-{(-94.3) + (-71.7)} kcal/mole Temperature, T is 25degrees = 298.

15K ΣnSproducts - ΣmSreactants = {(197.8+256.7)-(213.6+248.8)} (Standard entropies) = 44.7- 298.15(-7.5) = 2280.8kcal. #4 Solutions Oxidation is a chemical process that occurs when there is loss of an electron or electrons by a reactant in a chemical reaction. Example Chemical reaction between Zinc metal and sulphuric acid is a good example of an oxidation reaction. Zn(s) + 2 HCl (aq) ZnCl2 (aq) + H2 (g) The equation is broken down to ionic equation as shown below Zn(s) + 2 H+ (aq) + 2 Cl-(aq) Zn2+ (aq) + 2 Cl-(aq) + 2 H2 (g) Zinc ions are oxidized as shown below Zn(s) Zn2+ (aq) + 2 e- On the other hand, reduction is a chemical process that occurs when there is a gain of an electron or electrons by a reactant in a chemical reaction.

Example In the equation above hydrogen is reduced as shown below. Hydrogen ions react by gaining electrons to form hydrogen gas. Hence this is a reduction reaction. 2 H+ + 2 e-  H2 (g) #5 Solutions Alkalinity- This is the measurement of the ability of an aqueous solution to be able to neutralize an acid. First step is to measure the quantity of acid required to bring the ph of the sample under test to around 4.2 At this point, it is evident that all the alkaline compounds have been used up in the sample.

Water hardness- This is the measurement of the quantity or level of calcium and magnesium salt presence in water. An indicator reagent, blue in color for pure water is added to the water under test. If the water contains calcium or magnesium ions, a red complex is formed due to the reaction with the indicator. A titrant, ethylenediaminetetraacetic acid, is added drop by drop until chelation of both calcium and magnesium ions are achieved. The indicator then turns to its original blue color.

PH- This refers to a scale that is used to determine whether an aqueous solution exhibits acidity or alkaline properties A PH test strip can be used to measure PH. Dip the ph test strip in the solution whose PH is to be measured. Compare the color to the color chat to get the actual ph of the solution #6 Solutions Conductivity- Through conductivity, the quantity of inorganic solids dissolved in water can be established. Some of the inorganic solids include nitrates and sulphates. Organic compounds are poor electric conductors hence their presence in water can also be established.

Turbidity- Through turbidity, it is easier to determine the amount of particles that are suspended in water. This is achieved by the amount of light that can pass through water. Color- Water color can make water unpleasant to drink and can influence other factors such as the presence of soil particles in water favor bacterial growth. DOC- This is very crucial during the water treatment process as it can cause carcinogenic disinfection which is harmful to the body. #7 Solutions NOM- Natural Organic Matter TOC- Total Organic Carbon UV- Ultra Violet DOM- Dissolved Organic Matter Reference Sarai, D. (2005). Basic Chemistry for Water and Wastewater Operators (Revised ed., p 196). Mumbai.