CHM152GW2 S09 Key

Chemistry (MasteringChemistry Series)

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Unformatted text preview: Group Work 2, CHM 152, Burk, Names: ______________Key____________________ due 2-13-09 3pm Papers will NOT be accepted after 3pm because I need to post the key so you can study for the exam over the weekend. 1. Consider the following mechanism: elementary step one: elementary step two: H2O2(aq) + I-(aq) H2O(l) + OI-(aq) H2O2(aq) + OI (aq) H2O(l) + O2(g) + I-(aq) a. What is the intermediate? ____ OI-(aq)_______ b. What is the catalyst? _______ I-(aq)________ c. What is the overall reaction? 2H2O2(aq) 2 H2O(l) + O2(g) d. What is the molecularity for step one? ________bimolecular______ e. What is the molecularity for step two? __________ bimolecular___ f. If the real rate law is rate = k[H2O2][OI-] then which step is rate determining? ___Step two_____ 2. Circle true or false. a. Most collisions results in product formation. True False b. If the [reactant] increases, the rate increases. True False c. If the collision energy is greater than the activation energy, products always will form. True False 3. The activation energy for a reaction is 106 kJ/mol. At 298 K the rate constant is 3.46 x 10-5 s-1. At what temperature is the rate constant 9.63 x 10-5 s-1? Show your work and circle your answer. a. 0.305 K b. 305 K c. 328 K d. 829 K e. 291 K 1 3.46 x 10 9.63 x 10 5s 5s 1.024 1 1 106000 12749.6 0.0000803 0.00328 1 8.314 1 1 1 1 1 298 1 298 1 298 4. What is the name for a positive electron? ______positron_________ 5. What exactly is an alpha particle made of? helium nuclei (2 neutrons & 2 protons) 6. Americium-241 is used in smoke detectors and it is an alpha emitter. Write the alpha decay reaction. 7. Write the beta decay reaction for strontium-90. 8. Write the positron decay reaction for iodine-124, which is used in therapeutic PET scans. 9. Write the electron capture reaction for aluminum-26. 10. Fill in the blank. 23 11Na + _____ 11. Fill in the blank. 59 27Co + 1 0n 24 ______ 56 25Mn 11Na + ____ + 1 1H _______ 12. Magnesium-28 has a half-life of 21.0 hours. How much of a 34.5 gram sample would remain after 4.00 days? Show your work. 2 ⁄ 96 2 21.0 34.5 . . 34.5 0.0421 . ...
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This document was uploaded on 09/27/2011.

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