Download CHEM 103, Section 32 (DeVoe) - Exam 1 - Prof. Howard J. Devoe and more Exams Chemistry in PDF only on Docsity! CHEM 103, Section 32 (DeVoe) YOUR NAME (printed) _______ Exam 1 February 16, 1995 (Circle)the name of your TA: Anamitro Brian Dino Jack John ^lanYJndff^ IvJ^e Jin This exam has a total of 100 points. Please make sure you have all five pages. Do not write in this space 1-14____728 15.____78 16.____78 17.____78 18.____74 19.____74 20. ____78 21. ____74 22. ___/4 23. ____74 24. ____78 25. ____76 26. ____76 TOTAL ______7100 PART I. Fourteen multiple-choice questions (2 pts each, 28 pts total). Write the letter (A, B, etc.) of the one best answer for each question on the line at the right. 1. The number of milliliters in one cubic meter is A) 103 B) 104 C) 105 D) 10fi E) 107 _ 2. One inch is 2.54 cm. If a postage stamp is 2.5 cm long and 2.1 cm wide, its area in square inches is closest to A) 0.72 in 2 B) 0.81 in2 C) 1.2 in 2 D) 2.1 in 2 E) 5.3 in2 3. In chemistry, a solution is defined as A) an element B) a compound C) a homogeneous mixture D) a liquid that contains water 4. One millisecond is equal to A) 10~ 9 s B) 10~6 s C) lO-3 s D) 103 s E) 1C)6 s F) 109 s 5. One H2O molecule measures about 3 x 10" 1 nm across. Expressed in centimeters, this distance is A) 3 x 10~ 8 cm B) 3 x 10~ 12 cm C) 3 x 1010 cm D) 3 x 10~9 cm E) 3 x 10~ 10 cm 6. Two different isotopes of the same element have the same A) mass number B) atomic weight C) number of neutrons D) number of protons 7. The average mass of one carbon atom in a sample of CO2 is A) exactly 6 g B) exactly 6 u C) exactly 12 g D) exactly 12 u E) 12.01 g F) 12.01 u 8. 32 grams of oxygen (O2) contains A) 2 oxygen atoms B) 1.0 mole of oxygen atoms C) 6.0 x 1023 O2 molecules D) 32 moles of oxygen atoms 9. A compound has the empirical formula CH and a molar mass of approximately 78 g7mol. The molecular formula is A)CH B)C2H2 C)C6H6 D) C5 H 18 E) C4H4 10. Which of the following ionic compounds is expected to be most soluble in v/ater? A) FeS B) CaCO3 C) (NH4) 2S D) PbSO4 E) AgCl -2- 11. The molar mass of NaCl is 58.44 g/mol. The mass of NaCl needed to prepare 2.00 L of 0.300 M NaCl solution is closest to A) 0.0103 g B) 0.114 g C) 8.77 g D) 35.1 g E) 390. g 12. If you dilute 5.00 mL of 0.300 M NaOH with water to a total volume of 15.00 mL, what is the concentration of solute in the dilute solution? A)4.00xlO"3 M B) 0.0444 M Q0.100M D) 0.900 M E) 10.0 M 13. The oxidation state of manganese in the MnO4~ ion is A) -2 B) -1 C) +1 D) +4 E) +7 F) +8 14. In the reaction of 2.5 moles of F2 with an excess of NH3 by the reaction 5F2 + 2NH3 > 6HF + N2F4 , the maximum amount of HF that can be produced is A)3.0molHF B) 2.1 mol HF C) 7.5 mol HF D) 5.0 mol HF E) 0.48 mol HF PART II. Short answers. Only the answers written on the lines or in the spaces will be graded. 15. (8 pts) One atom of nitrogen-15 has __ electrons, __ protons, and __ neutrons; its mass (to the nearest whole number) is __ u. 16. (8 pts) Write the chemical formula of: (a) ammonium sulfate (b) mercury(I) iodide (c) iron(III) sulfide (d) dinitrogen trioxide 17. (8 pts) Write the name of each of the following compounds: (a) LiHCO3 (b) KF (c) Cu(N03 ) 2 (d) SnO2 18. (4 pts) Balance the following equation by writing whole-number coefficients where needed: MgO(s) + Fe(s) -> Fe2O3 (s) + Mg(s)
