Chemistry 1A - Fall 2000 - Pines - Midterm 3

C when wood burns its weak bonds break to combine

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Unformatted text preview: . C.) When wood burns, its weak bonds break to combine with the stronger oxygen-oxygen double bonds, releasing energy. D.) When you burn wood, the products are more stable than the reactants so energy is released. E.) When wood is a reactant, its high energy bonds release energy when they break. Page 4 of 4 Name:_________________________________________ 11.) Consider the dissociation reaction A2 (g) 2 A (g). The following pictures represent one possible initial state and the equilibrium state for the system. Initial State Equilibrium State Which of the following statements is true for this dissociation reaction? A.) This reaction favors products at all temperatures because the number of A atoms increases and the number of A2 molecules decreases. B.) This reaction favors reactants at all temperatures because the A2 molecules have a bond which makes them more stable. C.) This reaction favors reactants at lower temperatures because heat is absorbed. D.) This reaction favors reactants at higher temperatures because heat is absorbed. E.) This reaction doesn’t favor products or reactants since the equilibrium constant equals 1. 12.) Which process is accompanied by the largest increase in entropy? I II III A.) I!V IV B.) I!II D.) III!IV V C.) II!III E.) IV!V Page 5 of 5 Name:_________________________________________ Part 2: Short Answer Problems (107 pts total) Instructions: Enter answers for all questions in the boxes provided (or as otherwise instructed). Show your work. Where requested write explanations in fifteen words or less. 1.) (60 pts) Consider the following reaction: CO2(gas) + H2(gas) CO(gas) + H2O(liquid) o At equilibrium at 25 C, PCO2 = PH2 = 1.0 atm ; PCO = 3.2 x 10-4 atm . a.) The volume is suddenly reduced by a factor of ½. What are Q and K? How will the reaction proceed toward equilibrium? K = PCO/ PCO2 PH2 = 3.2 x 10-4 Q: 1.6 x 10-4 After reduction in volume: P*CO2 = P*H2 = 2.0 atm P*CO = 6.4 x 10-4 atm K: 3.2 x 10-4 Q = P*CO/ P*CO2 P*H2 = 1.6 x 10-4 K = 3.2...
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This note was uploaded on 09/11/2009 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at University of California, Berkeley.

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