15.2 Born-Haber Cycle Our calculations of enthalpies so far have involved covalent substances. Now we need to look at the enthalpy changes involved in the formation of giant ionic lattices. Lattice enthalpy is defined as either the: ’the enthalpy change that occurs when one mole of a solid ionic crystal is broken into its ions in the gaseous state‚ at standard temperature and pressure. Because all the bonds in the ionic lattice are broken‚ it is an endothermic process‚ ∆H is positive. ’ The
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Determining the Stoichiometry of Chemical Reactions Mrs. Farrales Nikita Pandya October 23‚ 2012 December 3‚ 2012 INRODUCTION In the method of continuous variations the total number of moles of reactants is kept constant for the series of measurements. Each measurement is made with a different mole ratio of reactants. A mole ratio
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primary objective of this lab is to be able to determine the specific heat of a reaction by using a calorimeter. A calorimeter is a device used to determine the specific heat of chemical reaction or a physical change. The specific heat a reactions is used to refer to the amount of heat that is lost or gained when one gram of a particular substance increases or decreases by one degree Celsius. When a chemical reaction occurs in an open container most of the energy gained or lost is in the form of
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Copper and Zinc Composition Percentages in Pennies Introduction. The United States Mint sends copper and zinc to a fabricator‚ which creates coin-sized discs called planchets. The planchets undergo the coining press at the Mint where they are stamped as genuine United States legal tender coins. The purpose of this experiment is to determine the accuracy of the copper and zinc composition percentages in a random sampling of pennies. The penny was dissolved to make aqueous copper ions and four copper
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QUANTITATIVE DETERMINATION OF COPPER (II) CONCENTRATION BY SPECTROPHOTOMETRY D.DEL PRADO1‚ J. BELANO1‚ M.MAHUSAY2‚and M.FRANCISCO2 1 DEPARTMENT OF FOOD SCIENCE AND NUTRITION‚ COLLEGE OF HOME ECONOMICS 2INSTITUTE OF CHEMISTRY‚ COLLEGE OF SCIENCE UNIVERSITY OF THE PHLIPPINES‚ DILIMAN‚ QUEZON CITY 1101‚ PHILIPPINES DATE SUBMITTED: 12 MARCH 2013 DATE PERFORMED: 7 MARCH 2013 ------------------------------------------------- ------------------------------------------------- ABSTRACT -------------------------------------------------
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Journal of Bangladesh Academy of Sciences‚ Vol. 35‚ No. 2‚ 203-210‚ 2011 CRYSTALLIZATION OF ZINC SULPHATE SINGLE CRYSTALS AND ITS STRUCTURAL‚ THERMAL AND OPTICAL CHARACTERIZATION J.K. SAHA AND J. PODDER* Department of Physics‚ Bangladesh University of Engineering and Technology‚ Dhaka-1000‚ Bangladesh ABSTRACT Zinc sulphate (ZnSO4.7H 2O)‚ an inorganic material has been crystallized by an isothermal evaporation method. ZnSO 4.7H2O is highly soluble in water and the solubility is found to be increased
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Determining the Enthalpy of a 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
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Thermochemistry: An Ice Calorimeter Determination of Reaction Enthalpy Curtis M. Franklin Thursday‚ February 14‚ 2013 ABSTRACT An ice calorimetric measurement was used to determine that a reaction involving solid magnesium metal and 1.00M sulfuric acid produces an experimental a value of ∆H = -226 ± 28 kJ/mol at 0°C. This is about 48.4% lower than the expected value reported at 25°C. Introduction Many chemical reactions exhibit themselves by exchanging heat energy‚ either be absorbing
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2013 Determining the Mole Ratios in a Chemical Reaction Introduction The purpose of this lab was to determine the mole ratios of the reactants hypochlorite ion (OCI ) and thiosulfate (S O ) when reacted in a chemical reaction. A chemical equation gives the mole ratios of the reactants and products involved in the chemical reaction. When some formulas of the products are not known‚ experimental measurements can be made to determine those ratios. During this reaction‚ hypochlorite
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Section Assignment 3.4 Part F – The Reaction of Iron Nails with a Copper Solution Introduction: The experiment in this activity involves the reaction between a copper (II) chloride solution with iron nails and the mole ratios involved in the reaction. Measurements are taken to determine the moles of each reactant involved in the reaction and thus the number of atoms or molecules involved. Apparatus and Materials: Refer to the reaction of iron nails with a copper solution assignment in Module 3
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