EXPERIMENT 11: DETERMINATION OF DISSOLVED OXYGEN IN A WATER SAMPLE (WINKLER METHOD) INTRODUCTION In an alkaline solution‚ dissolved oxygen will oxidize manganese(II) to the trivalent state. 8OH-(aq) + 4Mn2+(aq) + 2H2O(l) －－＞ 4Mn(OH)3(s) The analysis is completed by titrating the iodine produced from potassium iodide by manganese(III) hydroxide. 2Mn(OH)3(s) + 2I-(aq) + 6 H+(aq) －－＞ 2Mn2+(aq) + I2(aq) + 6H2O(l) Sodium thiosulphate is used as the titrant. Success of the method is critically
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Introduction The major component of eggshells is calcium carbonate (CaCO3). Calcium carbonate cannot be dissolved in water‚ but can dissolve in an acid using the reaction: 2HCl(aq)+CaCO3(s) Ca2+(aq)+CO2(g)+H2O+2HCl-(aq) This reaction is not used to titrate the CaCO3 because it is very slow when the reaction is close to the endpoint. Instead adding an excess of acid to dissolve all of the CaCO3 and then titrating the remaining H3O+ with NaOH solution can achieve the determination of the amount
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Heat of Formation of Magnesium Oxide Objetive: To determine the heat formation of MgO (Magnesium Oxide) using Hess’s Law‚ which states the heat within a chemical reaction is independent of the pathway between the initial and final states. Introduction: Chemical reactions require heat energy to complete‚ called an endothermic reaction‚ or produce heat energy‚ and thus called an exothermic reaction. The heat energy produced by such reactions can be measured using a calorimeter‚ a piece
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ADVANCED LABORATORY I FALL‚ 2000 ADIABATIC CALORIMETRY Reference: S‚G‚&N Exp. 8 in Chp. VI. Objectives: (1) Determine the integral heat of solution for finite amounts of KNO3 dissolved in water. Extrapolate the measurement to infinite dilution to obtain the differential heat of dilution. (2) Incorporate the concepts learned in your Electronics laboratory to amplify and accurately measure temperature changes associated with solution formation. (3) Use the A/D capabilities of a computer to record voltage
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[Date Place INDOOR AIR POLLUTION Children’s Health and the Environment WHO Training Package for the Health Sector World Health Organization www.who.int/ceh July 2008 version 1 Indoor Air Pollution Indoor LEARNING OBJECTIVES LEARNING TO UNDERSTAND‚ RECOGNIZE AND KNOW: Hazards of indoor air pollution to children’s health Different toxicants in indoor air‚ according to sources‚ settings and activities Characteristics and issues relating to indoor air pollution in industrialized
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also known as the water flea are planktonic crustaceans that are found in lakes‚ ponds‚ and streams. They received “their common name from their jerky movement through the water” (Clare). They are also “very small‚ usually 2-5mm long‚ with an overall shape similar to a kidney bean” (Elenbaas). Daphnia play an important role in the freshwater food chains and serve as food for other freshwater organisms such as fish. They are also commonly used to test for chemical toxicity in water. Since Daphnia have
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2015 August Heat Many people say that life is full of remarkable concurrence of events or circumstances without apparent causal connection‚ some of them are more risky than others. More danger sides of coincidences are shown by William Fryer Harvey‚ the story August Heat shows that how irrational fears are created by one’s mind when they face a horrific coincidence. This story took place in England during summer. The heat at that time is enough to make a person mad. In “August Heat” the use of setting
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Topic 6 Water Quality and Water Management What determines water quality? Drinking water should be colorless‚ odorless and flavorless; this means that there are no organisms and sediments in the water‚ but it does not mean that if your drinking water look‚ smells and taste clean‚ that does not mean that there is nothing else it. Water also contains dissolved solids: •Sulfur •Calcium •Magnesium If water contains a lot of dissolved calcium and magnesium it is called hard water
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place directly affected by the outdoor environment‚ excessive of temperature above 35*C‚ hot air in work place. Humidity Directly affected humid outdoor conditions‚ excessive of humidity above 80%‚ steam or heat producing source or equipment‚ completely wet skin condition of workers. Heat Radiation Working under direct sunlight‚ sources / heat generating facilities (e.g. fire‚ welding‚ hot surfaces and machinery) in close proximity to
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Laboratory Experiment no. 2 The Living Plant Cell Objectives: * To study the different types of plant cells. * To observe plant cells as to their shapes‚ structures and function. Materials: Microscope cover slip glass slide water onion Iodine soln. hydrilla salt tomato razor blade Medicinal dropper epidermal tissue of rhoeo-discolor Procedure: 1. Onion Cell 1. Prepare an onion bulb 2. Place a drop of water at the center
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