Name. Student ID # CHEMISTRY 121 [Tyvoll] EXAM I. September 30, Possibly Useful Information:

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1 Name Student ID # CHEMISTRY 121 [Tyvoll] EXAM I September 30, Possibly Useful Information: 1) ( ) ( ) ( ) ( ) ( ) 1 in = cm 1 kg = lb 2) ( ) ( ) ( ) ( ) ( ) R = J K -1 h = 6.63 x J s 3) ( ) ( ) ( ) ( ) ( ) N = x c =3.0 x10 8 m/s 4) ( ) ( ) ( ) ( ) ( ) 1 cup = L 1 L = 1000 cm 3 5) ( ) ( ) ( ) ( ) ( ) 1 mile = km 1 league = 2.60 miles 6) ( ) ( ) ( ) ( ) ( ) R = L atm / mol K 7) ( ) ( ) ( ) ( ) ( ) 1 hectare (ha) = 10,000 m 2 8) ( ) ( ) ( ) ( ) ( ) 9) ( ) ( ) ( ) ( ) ( ) 10) ( ) ( ) ( ) ( ) ( ) 11) ( ) ( ) ( ) ( ) ( ) 12) ( ) ( ) ( ) ( ) ( ) 13) ( ) ( ) ( ) ( ) ( ) 14) ( ) ( ) ( ) ( ) ( ) 15) ( ) ( ) ( ) ( ) ( ) Points Missed: Part I Part II

2 Grade (100 Points Possible) Chemistry 121 (Tyvoll) Name EXAMINATION I (Please neatly print your name in the space above) September 30, 2004 Part I. Multiple Choice (3 points each -- Total points = 45.) Print your name in the space above and on the answer sheet. Choose the BEST answer for each of the following questions and blacken or mark an "X" in the correct space on the answer sheet. You should use a pencil to mark your answers. Make sure you carefully erase any incorrect answers. You may use the margins to do your work. Good luck!! 1. Which of the following is not a physical property? 1. color 4. hardness 2. thermal conductivity 5. flammability 3. density 2. What is the mass of 15.0 cm 3 of mercury if its density is 13.6 g/cm 3? g/cm g g g g 3. Which metric prefix means ? 1. kilo- 4. micro- 2. nano- 5. milli- 3. pico- 4. Converting 9.56 x 10-3 m to a unit that replaces the power of 10 by a prefix gives µm mm cm mm cm 5. A sugar cube is 9.2 mm along each edge. What is the total surface area of the sugar cube, in cm 2, expressed to the correct number of significant figures? Hint: a cube has 6 faces cm cm x 10 3 cm cm cm 2 6. Which one of the following is the symbol for potassium? 1. P 4. Pm 2. Pt 5. K 3. Po

3 7. How many atoms of each element does a unit of the compound Ca 3 (PO 4 ) 2 contain? 1. 3 calcium, 1 phosphorus and 4 oxygen 4. 3 calcium, 2 phosphorus and 6 oxygen 2. 3 calcium, 1 phosphorus and 6 oxygen 5. 3 calcium, 2 phosphorus and 8 oxygen 3. 3 calcium, 1 phosphorus and 8 oxygen 8. Conversion of 88.0 km/hour to m/s gives m/s m/s m/s m/s m/s 9. How many significant figures are there in the quantity, g? The mass ratio of calcium to oxygen in calcium oxide is : 1. What mass of calcium oxide should form when g of calcium is completely converted to calcium oxide by burning in pure oxygen gas, O 2? g g g g g 11. Which one of the following statements is not true? V 23 has an atomic number of Mo 42 contains 53 neutrons Zn 30 has the same number of electrons and protons Fe 26 has the same number of neutrons and protons C 6 has the same number of protons, neutrons and electrons 12. Assume that only two isotopes of argon, 40 Ar 18 (93.857%) and 43 Ar 18 (6.143%) exist in nature, where the atomic mass of Ar-40 is u, and the atomic mass of Ar-43 is u. If this were true, the atomic mass of argon, as shown on the periodic table, should actually be u u u u u 13. Calculate the number of grams in moles of fluorine (F 2 ) molecules g g g g g

4 14. What is the molar mass of thiophene, a compound used in the manufacture of pharmaceuticals, if its molecular formula is C 4 H 4 S u g/mol g/mol u g/mol 15. Determine the number of atoms of mercury (Hg) in a single drop of liquid mercury ( g/mol) if the drop has a mass of g x atoms x atoms x atoms x atoms x atoms

5 Part II - Total points = 55. Answer each of the following questions. SHOW ALL WORK! 1. (a) (5 points) Give the correct chemical formula for each of the following compounds: (1) barium hydroxide (2) diphosphorus tetrafluoride (3) silicon dioxide (4) sodium sulfate (5) copper(ii) bromide (b) (5 points) Give the correct chemical name for each of the following compounds: (1) NaHCO 3 (2) Fe(NO 3 ) 3 (3) HClO (4) N 2 O 5 (5) PCl 3 2. (5 points) Balance the following equations by inspection. Write the correct coefficients in the appropriate blanks also, if you mean a coefficient of 1, write it in the blank. (a) Al(s) + HCl(aq) AlCl 3 (aq) + H 2 (g) (b) PbO(s) + NH 3 (g) Pb(s) + N 2 (g) + H 2 O(l) (c) CCl 4 (l) + HF CCl 2 F 2 (l) + HCl(g) (d) KClO 3 (s) KCl(s) + O 2 (g) (e) C 8 H 18 (l) + O 2 (g) CO 2 (g) + H 2 O(l)

6 3. (10 points) You must show work to receive any partial credit! Phenol, C 6 H 6 O, is a general disinfectant that is strongly irritating to skin tissues and is toxic, both by ingestion and inhalation. If you have exactly 2.00 kg of C 6 H 6 O, (a) how many mols of C 6 H 6 O is this? (b) how many molecules of C 6 H 6 O is this? (c) how many O atoms is this?

7 4. (10 points) A fertilizer, commonly used here on the Eastern Shore, is The first number is the mass percent N (14.01 g/mol), the second is the mass percent P 2 O 5 ( g/mol) and the third is the mass percent potash, K 2 O (94.20 g/mol). So, if the active ingredients in are 10% N, 10% P 2 O 5, and 10% K 2 O, what is the mass, in kilograms, of potassium in 45.4 kg of fertilizer (a 100 lb. bag)? Show all work for credit!

8 5. (10 points) Adipic acid, C x H y O z, is an organic weak acid that is slightly soluble in water and is used in the manufacture of nylon and of polyurethane foams. Combustion analysis of pure adipic acid yielded the following elemental composition (weight percent): C, %; H, %; the remainder was oxygen (O). The molar mass of adipic acid was obtained by another type of analysis and was found to be g/mol. Use the data provided to determine (a) the empirical formula for adipic acid (You must show work for credit!) (b) the molecular formula for adipic acid (Show work!)

9 6. (10 points) A forensic chemist suspects that a sample is ethyl iodide. She weighed a dry and empty pycnometer and found its mass was g. When she completely filled the pycnometer with distilled water at 20 o C, its mass was g. Finally, when dried and then filled with the unknown organic liquid, the same pycnometer plus the organic liquid had a total mass of g. If the density of distilled water is g/ml at 20 o C, (a) calculate the volume of the pycnometer (Hint: round your answer to the maximum allowable, correct number of significant figures) (b) Now calculate the density of the unknown organic liquid at 20 o C (c) The unknown liquid is most likely which one of the following liquids? (a) 2-iodoethanol ( g/ml) (b) 1,1,2-tribromoethane ( g/ml) (c) ethyl iodide ( g/ml) (d) Was she correct in her suspicion? Explain briefly.

Name Student ID Number Lab TA Name and Time

Name Student ID Number Lab TA Name and Time CHEMISTRY 2A Exam I Fall 2012 - Enderle Instructions: CLOSED BOOK EXAM! No books, notes, or additional scrap paper are permitted. All information required is