Exam%201A%20F05%20and%20Key

Exam%201A%20F05%20and%20Key - CHEM 4:011 PRINCIPLES OF...

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CHEM 4:011 – PRINCIPLES OF CHEMISTRY I EXAM #1 (30 QUESTIONS, 1½ HOURS) 15-September-2005 FORM A 1. If you divide Avogadro’s number of pennies among the 6 billion people on earth, and if each person could count one penny per second every day of the year for eight hours per day, how long would it take to count all of the pennies? (A) Pass out the pennies now and we could get it done before the exam is over! (B) Depending on how I do in this class, the penny counting might be done before I graduate (in about 5 years). (C) It would take a lifetime, but if I live to be 100, I will see the job done. (D) The counting should be complete sometime around the turn of the next millennium. (E) It would take longer than human beings have existed on the earth, 9 million years or so. 2. A student is given an unknown that is either iron (II) sulfate or iron (III) sulfate. Which one of the following tests will be able to determine the identity of the solution? (A) Add NaCl because only Fe 2+ will precipitate with chloride. (B) Add Ba(NO 3 ) 2 because barium sulfate is insoluble in water. (C) Add HCl because Fe 3+ will neutralize the acid. (D) Add KMnO 4 because only Fe 2+ can be oxidized by MnO 4 - (E) Add Ca 2+ because only Fe 3+ can be reduced by Ca 2+ . 3. A student reported the compositions (mass %) below for five different oxides of nitrogen. Which one is not consistent with the law of multiple proportions? (A) 22.6%N, 77.4%O (B) 29.6%N, 70.4%O (C) 30.4%N, 69.6%O (D) 46.7%N, 53.3%O (E) 63.7%N, 36.3%O
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2 4. The oxidation numbers of P, S and Cl in H 2 PO 2 - , H 2 S and KClO 4 are, respectively: (A) -1, -1, +3 (B) +1, -2, +7 (C) +1, +2, +7 (D) -1, -2, +7 (E) -1, -2, +3 5. How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3 SCl 2 ( A ) + 4 NaF( s ) SF 4 ( g ) + S 2 Cl 2 ( A ) + 4 NaCl( s ) (A) 1940 g (B) 1510 g (C) 754 g (D) 205 g (E) 51.3 g 6. The earth quake responsible for the December 2004 South Asian tsunami shifted the Earth’s North Pole by 2.5 cm. Assuming the motion is in the same direction, how many such earth quakes would be necessary to move the North Pole 1.0 foot? (1 in = 2.54 cm, 12 in = 1 ft ) (A) 4 (B) 5 (C) 10. (D) 12. (E) 30. 7. Select the net ionic equation for the reaction between lithium hydroxide and hydrobromic acid. LiOH( aq ) + HBr( aq ) H 2 O( A ) + LiBr( aq ) (A) LiOH( aq ) Li + ( aq ) + OH - ( aq ) (B) HBr( aq ) H + ( aq ) + Br - ( aq ) (C) H + ( aq ) + OH - ( aq ) H 2 O( A ) (D) Li + ( aq ) + Br - ( aq ) LiBr( aq ) (E) Li + ( aq ) + OH - ( aq ) + H + ( aq ) + Br - ( aq ) H 2 O( A ) + LiBr( aq )
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Exam%201A%20F05%20and%20Key - CHEM 4:011 PRINCIPLES OF...

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