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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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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[ 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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Constant of an Unknown Ester Hydrolysis Reaction Abstract The experiments to follow determined that the equilibrium concentrations of the reaction: ester + water ↔ alcohol + acid‚ are equal to 0.0363 moles of ester‚ 0.2852 moles of water‚ and 0.0268 moles each of alcohol and acid. Using this information the equilibrium constant was determined to be 0.06938. 1. Introduction In this lab the equilibrium constant‚ Kc‚ for the acid catalyzed reaction between an unknown ester and water
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Computer The Determination of a Chemical Formula 1 Second‚ you will conduct a chemical reaction with the dried sample‚ which will produce elemental copper. By measuring the mass of copper that forms‚ you will have the necessary information to determine the moles of copper and chlorine in your sample‚ and you will be able to establish the proper chemical formula. OBJECTIVES • • • In this experiment‚ you will Ev al Determine the water of hydration in a copper chloride hydrate
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Report Submitted: September 4‚ 2013 Title: Observations of Chemical Changes Purpose: To observe some properties of chemical reactions and to associate chemical properties with household products. Procedure: In this experiment I used a 96-well plate to hold each of the chemical reactions that occurred during this lab. Using a pipet‚ I added two drops of one chemical with two drops of another chemical and observed the effects of each reaction. Data Table 1: Experimental Data Well # |
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