chem midexam 1-MCEx1Practice

chem midexam 1-MCEx1Practice - Chemistry 142 Multiple...

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Chemistry 142 Multiple Choice (a) Before starting, please check to see that your exam has 6 pages, which includes the periodic table. (b) Fill in your name, section, and student number on Side 1 of the Answer Sheet . (c) To receive credit, you must mark Test Version A on Side 1 of the answer sheet. (d) When you are done with the exam, hand the Answer Sheet to a TA at the exit of the room. Please take the questions with you. (e) The exam is over at 6:20 AM. No answer sheet will be accepted after 6:20 AM. (e) Our final exam is scheduled for MONDAY, DECEMBER 14 at 6:30 PM in this room.
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Chem 142 Midterm I 2009 October Page 2 This is test version A . To receive credit you must mark version A on side 1 of the Answer Sheet. 1. (3 points) The result of (3.8621 × 1.565) – 6.04 is properly written as a. 0.00 b. 0.004 c. 0.0042 d. 0.00419 e. 0.004186 2. (8 points) When 3.0 L of hydrogen gas (H 2 ) reacts with 1.0 L of nitrogen gas (N 2 ), 2.0 L of gaseous product are formed. All volumes of gases are measured at the same temperature and pressure. What is the formula of the product? a. N 2 H 6 b. NH 4 c. NH d. N 2 H 3 e. NH 3 3. (8 points) The transition metal rhenium has two stable isotopes. The atomic mass of rhenium is 186.2 g/mol. Given that 37.1% of natural rhenium is 75 185 , what is the other stable isotope? Re a. 189 75 Re b. 190 75 Re c. 183 75 Re d. 187 75 Re e. 181 75 Re
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Chem 142 Midterm I 2009 October Page 3 4. (8 points) The compound, P 4 S 10 , is used in the manufacturing of safety matches. What is the compound’s name? a. tetraphosphorus decasulfide b. phosphoric sulfide c. phosphorus decasulfide d. phosphorus sulfide e. phosphorus sulfate
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Chem 142 Midterm I 2009 October Page 4 5. (8 points) Which is not the correct chemical formula for the compound named? a. sodium sulfate Na 2 SO 4 b. potassium chloride KCl c. ammonium sulfide (NH 4 ) 2 S d. barium hydroxide Ba(OH) 2 e. calcium oxide Ca 2 O 6. (8 points) Calculate the number of oxygen atoms in 29.3 g of sodium sulfate, Na 2 SO 4 (molar mass = 142.05 g/mol). a. 1.24 × 10 23 O atoms b. 2.48 × 10 23 O atoms c. 4.97 × 10 23 O atoms d. 2.94 × 10 24 O atoms e. 1.18 × 10 25 O atoms 7. (8 points) Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. If its molar mass is between 94 and 98 g/mol, what is its molecular formula? a.
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This note was uploaded on 01/31/2010 for the course CHEM 142 taught by Professor Zoller,williamh during the Spring '07 term at University of Washington.

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chem midexam 1-MCEx1Practice - Chemistry 142 Multiple...

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