Exam-1-Spring'11-Karlin-Answers - Exam I Name_ANSWERS...

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1 Exam I Name ____ANSWERS______ Introductory Chemistry 030.101(Print) Last Name First Name Section 1Prof. K.D. Karlin Feb. 25, 2011 Student ID # (if you know it) __________ (10 problems, 110 points) SHOW ALL WORK FOR FULL/PARTIAL CREDIT Data attached:Electrochemical Redox Potentials Table Som Information: Recall, pH = –log[H+] R = 8.315 J K–1mol–1ΔE = Δ– 0.592/n log1.(10)The drain cleaner Drano consists of aluminum turnings mixed with sodium hydroxide. When it is added to water, the sodium hydroxide dissolves and releases heat. The aluminum metal reacts with water to generate bubbles of hydrogen gas and aqueous Al(OH)4ions. Write a balanced net ionic equation for the reaction. (You would do well to also show the balanced half-reactions) 10Q
2 (g)
2 OH
e
(10)If concentrations are measured in moles per liter, and time in seconds, what are the units of the rate constant for (a) a first-order reaction
(b) a third-order reaction Answer________________ (c) The radioactive potassium isotope 42K, which decays in a first-order process, has a half-life of about 12 hours. What is the fractionof the initial concentration of 42K remaining after 48 hours?
1/16
Answer_______________________3.(10)Cu+does not exist in appreciable concentrations in aqueous solutions, because it reacts (in a disproportionation reaction) to give Cu2+plus metallic copper (Cu(s)) Show this is true by showing how this reaction is thermodynamically favorable.

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