1CHEM 107 (Spring-2004) Exam 1 (100 pts) Name: ------------------------------------------------------------------------, SSN -------------------------------- LAST NAME, First (Circle the alphabet segment of your LAST NAME): A-C D-H I-L M-O P-Z Please answer the following questions: Part I: Multiple Choices (48 pts: 16 @ 3 pts each). Circle the ONE best answer: 1. Perform the indicated operations and give the answer in cm with the proper number of significant figures. 12.64 cm – 48 mm + 0.246 m = ? a) 42.0 b) 32.44 c) 32.4 d) 42 2. Two atoms are 154 pm apart. Express this distance in cm. a) 1.54 x 10-8 b) 1.54 x 10-10 c) 1.54 x 10-12 d) 1.54 x 108 3. Which of the following does not represent a chemical property? a) flammability in air b) burning gasoline c) boiling an egg d) solubility in water 4. Convert 1.39 ft/s to meters per minute (1 m = 39.37 in). a) 1520 b) 305 c) 2.12 d) 25.4 5. A bottle containing 500 mL of ketchup has a density of 1.43 g/mL. What is the mass of the bottle in grams? a) 350 b) 715 c) 71.5 d) 501 6. Taken by itself the fact that 8.0 g of oxygen and 1.0 g of hydrogen combine to give 9.0 g of water demonstrates what natural law? a) Conservation of Mass b) Constant Composition c) Periodicity e) Multiple Proportions 7. What is the nuclear symbol for a species which contains 57 neutrons and has a mass number of 101? a) Er b) Ru c) Md d) Os28. Predict the product of the reaction of aluminum, Al with selenium, Se. a) Al2Se3 b) Al3Se2 c) AlSe d) AlSe3 9. Which of the following statements about the periodic table is incorrect? a) Group 17 is the only group which has the three physical states of matter. b) Group 18 is called noble gases group c) Group 1 is called alkali metals d) Non of the above 10. Calculate the mass of a single Mg atom (atomic mass = 24.30 amu)? a) 4.035 x 10-23 b) 4.035 x 10-25 c) 1.661 x 10-24 d) 2.478 x 10-24 11. What is the number of molecules that contained in 1.598 g sample of Br2 (molar mass of Br2 = 159.8 g)? a) 6.022 x 1023 b) 0.01 c) 6.022 x 1021 d) no answer was given 12. All of the following statements are true EXCEPT a) a proton carries a +1 charge and an electron carries -1 charge. b) a neutron is an uncharged particle with a mass slightly greater than a proton. c) more than 99.9% of an atom’s mass is concentrated in the nucleus. d) the nucleus of an atom has a negative charge. 13. How many electrons, protons, and neutrons are found in a Cl- ion formed from 35Cl? a) 17 electrons, 16 protons, 19 neutrons b) 17 electrons, 17 protons, 18 neutrons c) 18 electrons, 17 protons, 18 neutrons b) 18 electrons, 18 protons, 18 neutrons 14. Naturally occurring lithium consists of two isotopes Li-6 and Li-7. The atomic mass of Li is approximately 6.9. What are the reasonable estimate of the relative percentages of Li-6 and Li-7, respectively? a) 10, 90 b) 25, 75 c) 50, 50 d) 90, 10 15. Which of the following compounds is ionic? a) SF6 b) PCl3 c) PF3 d) CaCl2 16. Calculate the mass in grams of 0.100 moles of Ca(OH)2? a) 5.71 b) 7.41 c) 6.022 x 1022 d) 1.35 x 10-33Part II. Names, formulas and properties (28 pts: 14 @ 2 pts each) – NO Partial Credits 1. (16 pts) Complete the following table with the formula or the name of the compound Name Formula Vanadium(III) nitrate Lithium carbonate Calcium nitride Sulfuric acid CoF3 P2S5 Na3PO4 HF (aq) 2. (12 pts) Consider the following substances: Cl2, CaO, HBr, CuCl2, AsCl3, NaNO3 and NO2: a) Which are molecular (covalent)? ---------------------------------- b) Which are diatomic? ------------------------------------ c) Which are triatomic? ------------------------------------ d) In which we do find only electron sharing? ------------------------------------ e) Which compound is derived from a transition metal? ------------------------------------ f) Which compound is derived from a metalloid element? ------------------------------------- Part III. Calculations (24 pts): Show all work for full credit. Please express all answers with the proper units and correct number of significant figures. 1. (8 pts) Naturally occurring copper is composed of two isotopes. One of the isotopes has an atomic mass of 62.9396 amu and 69.17% abundance. What is the atomic mass of the other isotope? Atomic mass of the second Cu isotope42. (16 pts) Strychnine, a deadly poison, has a molecular mass of 334 and a percentage composition 75.42% C, 6.63% H, 8.38% N and the balance oxygen. Calculate: a) the simplest formula of Strychnine b) the molecular formula of the compound a) Simplest formula b) Molecular formula5 Exam 1 – Spring 2004 You will have 60 minutes to complete this exam. The exam has 4 pages plus the Periodic Table Reference page. When you are told to do so, tear off the Periodic Table cover sheet and use as required during the exam. 1. 1 1 H 1.01 Periodic Table of the Elements 2 He 4.00 2 3 Li 6.94 4 Be 9.01 5 B 10.816 C 12.01 7 N 14.01 8 O 16.009 F 19.0010 Ne 20.18 3 11 Na 22.99 12 Mg 24.30 13 Al 26.9814 Si 28.08 15 P 30.97 16 S 32.0617 Cl 35.4518 Ar 39.95 4 19 K 39.1 20 Ca 40.08 21 Sc 44.96 22 Ti 47.8823 V 50.94 24 Cr 52.00 25 Mn54.9426 Fe 55.8527 Co 58.9328 Ni 58.6929 Cu 63.5530 Zn 65.3831 Ga 69.7232 Ge 72.59 33 As 74.92 34 Se 78.9635 Br 79.9036 Kr 83.80 5 37 Rb 85.47 38 Sr 87.62 39 Y 88.91 40 Zr 91.2241 Nb 92.91 42 Mo 95.94 43 Tc (98) 44 Ru 101.145 Rh 102.946 Pd 106.447 Ag 107.948 Cd 112.449 In 114.850 Sn 118.7 51 Sb 121.8 52 Te 127.653 I 126.954 Xe 131.1 6 55 Cs 132.9 56 Ba 137.3 57 La 138.9 72 Hf 178.573 Ta 181.0 74 W 183.8 75 Re 186.276 Os 190.277 Ir 192.278 Pt 195.179 Au 197.080 Hg 200.681 Tl 204.482 Pb 207.2 83 Bi 209.0 84 Po (209) 85 At (210) 86 Rn (222) 7 87 Fr (223) 88 Ra 226.0 89 Ac 227.0 104 Rf (261) 105 Db (262) 106 Sg (263) 107 Bh (262) 108 Hs (265) 109 Mt (266) 110 Uun(269) 111 Uuu(272) 112 Uub(277) 58 Ce 140.159 Pr 140.9 60 Nd 144.2 61 Pm(145) 62 Sm 150.463 Eu 152.064 Gd 157.265 Tb 158.966 Dy 162.567 Ho 164.968 Er 167.3 69 Tm 168.9 70 Yb 173.071 Lu 175.0 90 Th 232.091 Pa 231.0 92 U 238.0 93 Np 237.094 Pu