Chem Exam - ‘98 1. Solve the following problem related to the solubility equilibria of some metal hydroxides in aqueous solution. (a) The solubility of Cu(OH)2(s) is 1.72 x10–6 g/100. mL of solution at 25° C. (i) Write the balanced chemical equation for the dissociation of Cu(OH)2(s) in aqueous solution. Cu(OH)2 Cu 2+ + 2 OH – (ii) Calculate the solubility (in mol/L) of Cu(OH)2 at 25 °C. (1.72 x10–6 g/0.100 L)(1 mol/97.5 g) = 1.76 x10–7 mol/L (iii) Calculate
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Two-way reactions continue until equalibrium (the state at which there is balance between reactants and products) is reached. Discovering the equilibrium constant for a reaction is very helpful for understanding that reaction. Knowing the equilibrium constant of a reaction is important because it allows you to calculate how much product will ultimately be formed during a reaction. Moreover‚ it also tells you how a particular mixture of chemicals will react. This is because chemical reactions always
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Reactions in Aqueous Solutions: Metathesis Reactions and Net Ionic Equations Introduction: Metathesis or double decomposition reactions are a reaction in which two compounds react to form two new compounds‚ with no changes in oxidation number. The ions of two compounds exchange partners. AX + BY AY + BX This reaction can occur between two inorganic salts when one product is insoluble in water‚ driving the reaction forward. A typical example is as followed and is considered a molecular equation
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objective: In this experiment‚ I decided to find out how temperature would affect endothermic reactions compared to exothermic reactions. An endothermic reaction absorbs energy in the form of heat. This reaction feels cold because it is taking heat away from its surroundings. It also releases gases. An exothermic reaction is a reaction that releases energy as heat. Since the energy is released‚ the exothermic reactions feel hot. Methods/Materials I did three experiments. I mixed lemon juice and baking
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The total protein content was estimated as proposed by Lowry et al. A bovine serum albumin stock solution (1mg/ml) was prepared in sodium hydroxide (1N). Five different concentrations (0.2‚ 0.4‚ 0.6‚ 0.8‚ 1 ml) of the prepared solution were taken in different test tubes. In another set of test tubes‚ 0.1 and 0.2 ml of the extract were taken. In each test tube‚ the volume was made up to 1 ml‚ followed by addition of the prepared alkaline solution (5 ml) at room temperature. The solutions were left
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[ print page ] 04.05 Chemical Reactions: Combustion: Lab Worksheet and Rubric Before You Begin: You may either copy and paste this document into a word processing program of your choice or print this page. Procedure: 1. Iron (IIII) and copper (II) sulfate solution Fill a small test tube halfway with copper (II) sulfate solution. Add a 2.0 gram iron rod to the solution and observe the reaction. 2. Lead (II) nitrate and potassium iodide solutions Pour about 2.0 mL of lead (II) nitrate into
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purpose of this lab was to find the theoretical and experimental percentage yields of the double displacement reaction between the solutions Lead (II) Nitrate (PbNO3) and Potassium Iodide (KI). It is important to obtain amounts of Lead (II) Nitrate and Potassium Iodide as close to 1.44g as possible. This reaction creates Lead (II) Iodide and Potassium Nitrate. The precipitate during this reaction is Lead (II) Iodide. The balanced equation is Pb(NO3)2 + 2KI= PbI2 + 2KNO3. In this lab the Lead (II) Iodide
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difference between a mixture and a compound. A compound is a substance in which atoms of different elements are chemically held to one another. A mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs. A mixture can usually be separated back into its original components‚ a compound cannot. Below are some examples of the differences between each. Compounds •Compounds are pure substances. •They are made up of two or more elements combined
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Observations of Chemical and Physical Changes Derrick Davis Lab partner: None Location: My house Date Performed 25 Feb 15; 1600 CHE111-CO2 Photo 1 (Photo of me properly wearing safety goggles holding the student information card) Abstract: In chemistry it is important to understand the difference between physical and chemical changes. The objective of this experiment was to perform tests using heat or chemical mediators and observe the results for any physical or chemical changes. Various
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It was originally hypothesised that the reaction time would decrease with higher concentrations of the reactants‚ potassium iodate and sodium bisulfite as collision theory stated that more molecules present in a given volume meant a greater chance they would collide. Furthermore‚ the time was expected to decrease with higher temperatures as it influenced the reactant particles by raising their kinetic energy. However‚ the data collected from this experiment only partially supported this hypothesis
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