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Exam 1A F06&a - CHEM 4:011 PRINCIPLES OF CHEMISTRY I EXAM#1(30 QUESTIONS 1 HOURS 14-September-2006 FORM A 1 According to the given reaction 3 moles

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CHEM 4:011 – PRINCIPLES OF CHEMISTRY I EXAM #1 (30 QUESTIONS, 1½ HOURS) 14-September-2006 FORM A 1. According to the given reaction, 3 moles of Al 2 O 3 , plus 6 moles of C, plus 9 moles of Cl 2 will result in a theoretical yield of how many moles of AlCl 3 ? (You must first balance the equation.) Al 2 O 3 ( s ) + C( s ) + Cl 2 ( g ) AlCl 3 ( s ) + CO( g ) (A) 1 mole AlCl 3 (B) 3 moles AlCl 3 (C) 4 moles AlCl 3 (D) 6 moles AlCl 3 (E) 9 moles AlCl 3 2. Calculate the oxidation number of chlorine in perchloric acid, HClO 4 , a strong oxidizing agent. (A) 1 (B) +1 (C) +4 (D) +5 (E) +7 3. In the U.S. antifreeze is principally ethylene glycol, HOCH 2 CH 2 OH (a chemical so toxic that a teaspoonful will kill a cat). Congress is trying to mandate the use of a bitter additive to discourage children and pets from drinking antifreeze. What is the average molecular mass of ethylene glycol? (A) 31.03 amu (B) 34 amu (C) 48.26 amu (D) 60.05 amu (E) 62.07 amu
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4. In class, we determined the molecular formula for the caffeine molecule (structure shown at right). Determine the mass percent of nitrogen in caffeine. (A) 28.9% (B) 14.4% (C) 7.2% (D) 37.6% (E) 71.1% 5. If the density of nickel metal is 8.902 g/cm 3 , what is its density in kg/m 3 ? (A) 8.902 × 10 9 kg/m 3 (B) 8902 kg/m 3 (C) 8.902 kg/m 3 (D) 0.8902 kg/m 3 (E) 8.902 × 10 3 kg/m 3 6. Consider the two calculations (11.7 10.9) × 7.30 (i.e., subtraction first) and (11.7 × 7.30) (10.9 × 7.30) (i.e., subtraction last). Assuming these numbers are not exact, what are the correct results? (A) (11.7 10.9) × 7.30 = 6 and (11.7 × 7.30) (10.9 × 7.30) = 6 (B) (11.7 10.9) × 7.30 = 6 and (11.7 × 7.30) (10.9 × 7.30) = 5.8 (C) (11.7 10.9) × 7.30 = 5.8 and (11.7 × 7.30) (10.9 × 7.30) = 5.8 (D) (11.7 10.9) × 7.30 = 5.8 and (11.7 × 7.30) (10.9 × 7.30) = 5.84 (E) (11.7 10.9) × 7.30 = 5.84 and (11.7 × 7.30) (10.9 × 7.30) = 5.84 7. TNT (trinitrotoluene) is an explosive organic compound with an empirical formula of C 7 H x N y O z . Combustion analysis determines that TNT has the following mass percent content: C = 37.01%, H = 2.22%, N=18.50%. What is the empirical formula of TNT? (A) C
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This note was uploaded on 03/27/2008 for the course CHEM 4:12 taught by Professor Larsen during the Spring '08 term at University of Iowa.

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Exam 1A F06&a - CHEM 4:011 PRINCIPLES OF CHEMISTRY I EXAM#1(30 QUESTIONS 1 HOURS 14-September-2006 FORM A 1 According to the given reaction 3 moles

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