Questions2 - solid = 1.84 J/g o C, S liquid = 4.18 J/g o C,...

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Name: Chemistry 008, Spring 2008 Cornell University Dr. Pontrello Due 2/10/08 Learning Strategy Questions 2 Any time you write down a number, please include correct units when applicable. Clearly write any equation(s) that you are using to answer each question, and also clearly indicate the steps used to answer the questions, if appropriate. Part I: Methane. I.1 (14 points) You want to determine the standard enthalpy of formation of methane, but the reaction is really slow. Instead, you measure the standard enthalpy of formation of carbon dioxide (-393.5 kJ/mol CO 2 ), the standard enthalpy of formation of liquid water (-285.8 kJ/mol H 2 O), and the standard enthalpy change for the combustion of methane (-890.3 kJ/mol CH 4 ). What is the standard enthalpy of formation of methane? I.2 (9 points) How many grams of -10.0 o C ice would melt from the energy from the formation of 2.21 moles of methane under standard conditions? (values for water: S
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Unformatted text preview: solid = 1.84 J/g o C, S liquid = 4.18 J/g o C, q fusion = 6.01 kJ/mol) Name: 2 Part II: Diborane. II.1 (19 points) Diborane (B 2 H 6 ) is a colorless gas that can ignite spontaneously at room temperature. In the late 1940s there was much interest in using mixtures with diborane as rocket fuels. However, it was realized that diborane also forms boron oxides that reduced performance. The reaction of elemental B (s) and H 2 (g) does not generate diborane. Calculate the standard enthalpy of formation of diborane using the following measured reactions: The standard enthalpy of formation of B 2 O 3 (s) is -1271.9 kJ/mol B 2 O 3 (s). The standard enthalpy of formation of H 2 O (g) is -241.8 kJ/mol H 2 O (g). The standard enthalpy change of the following reaction is: B 2 H 6 (g) + 3 O 2 (g) B 2 O 3 (s) + 3 H 2 O (g) H o = -2032.9 kJ/mol B 2 O 3 (s)...
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This note was uploaded on 07/09/2008 for the course CHEM 342132 taught by Professor Davis during the Spring '08 term at Cornell University (Engineering School).

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Questions2 - solid = 1.84 J/g o C, S liquid = 4.18 J/g o C,...

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