BC '07 Exam 1

# BC '07 Exam 1 - University of Houston BCHS 3304 Exam I...

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University of Houston BCHS 3304 Exam I. Instructor: Dr. Briggs, Feb. 8, 2007 Printed Name_____ANSWER KEY ________ Answer all questions; show all work. Multiple choice – Circle the single letter (i.e. a., b., c., d., or e.) of the most correct answer on the EXAM, then mark it on the Scantron sheet with a #2 pencil. Mark BOTH the exam AND the Scantron sheet!! 1). What is a Brønsted base? (2 pts) a. A molecule that can accept a proton b. A molecule that can form a hydrogen-bond c. A molecule that has a net charge d. A molecule that can donate a proton e. A molecule that cannot form a hydrogen-bond 2). How many Å are there in 32.1 m? (2 pts) a. 32.1x10 -10 Å b. 3.21x10 -10 Å c. 0.321x10 -10 Å d. 32.1x10 10 Å e. 3.21x10 10 Å 1 Å = 1x10 -10 m; conversion factor = 1nm/1x10 -10 m nm 10 1 . 32 m 1 . 32 m 10 1 Å 1 ; m 10 1 Å 1 1 10 10 10 x x x x = = 32.1 m = 32.1x10 10 Å 3). How many femtoseconds are there in 23.1 ms? (2 pts) a. 2.31x10 -13 fs b. 23.1x10 -9 fs c. 2.31x10 15 fs d. 23.1x10 9 fs e. 2.31x10 13 fs 1 fs (femtosecond) = 1x10 -15 s; 1 ms (millisecond) = 1x10 -3 s fs x s x fs x ms s x x ms 13 15 3 10 31 . 2 10 1 1 10 1 1 . 23 = 4). How many kJ/mol are there in 5.67 kcal/mol? (2 pts) a. 1.36 kJ/mol b. 1,360 kJ/mol c. 23.7 kJ/mol d. 0.0237 kJ/mol e. 23,700 kJ/mol 1 kcal/mol = 4.184 kJ/mol mol kJ mol kcal mol kJ x mol kcal / 7 . 23 / 1 / 184 . 4 / 67 . 5 =

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