Chemical Reaction All chemical reactions involve an exchange of heat energy; therefore‚ it is tempting to plan to follow a reaction by measuring the enthalpy change (∆H). However‚ it is often not possible to directly measure the heat energy change of the reactants and products (the system). We can measure the heat change that occurs in the surroundings by monitoring temperature changes. If we conduct a reaction between two substances in aqueous solution‚ then the enthalpy of the reaction can be
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Determination of Iron by Reaction with Permanganate-A Redox Titration Purpose: The purpose of this experiment was to find the percentage of iron in an unknown iron oxide sample which could be determined through titration with a standard solution of potassium permanganate. Success in this analysis requires careful preparation and attention to detail. Performing this experiment also provides practice at titrations. The overall reaction is: 8H+(aq) + MnO4-(aq) + 5e- Mn2+(aq) + 4H2O Theory:
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DATE PERFORMED: JANUARY 6‚ 2011 SPECTROPHOTOMETRIC DETERMINATION OF THE EQUILIBRIUM CONSTANT OF A REACTION ABSTRACT The objective of the experiment was to determine the equilibrium constant of the reaction forming ferric thiocyanate through the use of Spectrophotometry. For the calibration‚ five standard solutions were prepared‚ then their respective absorbance values that were obtained through the use of the spectrophotometer‚ were plotted versus the concentration of the analyte so that a calibration
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Determination of Water in a Hydrate DESIGN – Aspect 1: Defining the problem & selecting variables Research Question: What percentage of Copper Sulfate Hydrate is water? Background Information: There are many ionic compounds that contain one or more waters of hydration in their formulae. They exists either in anhydrous or hydrated form. Most anhydrous compounds have a strong tendency to absorb water from the humidity in the atmosphere and shifts into a hydrated form. Because of
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Thermochemistry: An Ice Calorimeter Determination of Reaction Enthalpy Shannon Wedepohl 9/17/13 Abstract: During this experiment‚ an ice calorimeter was used to measure the change in volume in milliliters of magnesium metal and 1.00 M of sulfuric acid. We found the experimental molar enthalpy of the reaction to be ∆H = -370 ± 1 kJ/mol at 0˚C. This compares with an expected value of -466.9 kJ/mol at 25 ˚C‚ a 20.75% difference. Introduction: Many chemical reactions truly only encompass changes
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Determination of the Activation Energy of an Enzyme Catalysed Reaction PRACTICAL Report & Criterion Reference Grid * The expected sequence and details required for your practical report are outlined below. Please follow them closely‚ as they will facilitate the production of a structured report. * An introduction giving a synopsis of the experiment and the importance of rates of reaction and activation energy. This section should also state the aim of the practical (0.50-page) – 5 marks
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Findings Analysis to determine the sex of our case study AFA was done using a physical exam karyotyping and PCR-based sex testing. The results from our physical exams on AFA showed well-developed female external genitalia‚ presence of breasts‚ no menstrual cycle‚ and no facial or chest hair. This led to a conclusion that AFA is a sterile female. The results from the Karyotype Analysis showed presence of 22 pairs of autosomes chromosomes and two X’s revealing that she is female. Lastly the PCR-based
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GRAVIMETRIC DETERMINATION OF SULFATE Purpose You will be given a solid powder‚ which has been dried to constant mass. The sample is water soluble. The purpose of this experiment is to determine the concentration of sulfate in your solid sample using gravimetric analysis. Background Gravimetric Analysis The goal of most quantitative chemical analysis measurements is to estimate the relative abundance of an analyte in a chemical sample. For solid and liquid samples‚ a very common expression
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Determination of Chemical Formulae: The Reaction of Zinc and Iodine By Sarah Abstract: The main objective of this experiment was to use to the reaction between zinc and iodine to examine the validity of the Law of Conservation of Mass and the Law of Constant Composition. The Law of Constant Composition was tested by determining the mass of each of the reactants‚ zinc and iodine‚ and comparing their total to the mass of the zinc iodide product plus the excess zinc. The total mass of the reactants
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enzyme involves monitoring the change in absorbance of the reaction medium at 405 nm. Exergonic (i.e energy producing reactions) exhibit a negative free energy change. Sometimes these reactions occur spontaneously‚ but generally some energy must be supplied to initiate the reaction; in other word an energy barrier exists between the reactants and the products. The “energy barrier” represents the activation energy of a chemical reaction. In this practical the activation energy of hydrolysis
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