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Exam 1 – Version A Course: Instructor: Chemistry 100 Armando Herbelin x2882 [email protected] Calculator is OK, No notes. 50 min. Proctoring: Time Limit: Winter 2003 Name: _______________________ Be sure to select Letter (A/B/C/D/E) options on multiple choice questions. 1 1 H H 1.008 1.008 2.1 3 2 Atomic Number Symbol Atomic Mass Pauling’s Electronegativity 2.1 He 4.003 4 5 6 7 8 9 10 Li Be B C N O F Ne 6.941 9.012 10.81 12.01 14.01 15.99 19.00 20.18 1.0 11 1.5 12 2.0 13 Al 2.5 14 Si 3.0 15 P 3.5 16 S 4.0 17 Cl 26.98 28.09 30.97 32.07 35.45 1.5 1.8 2.1 2.5 3.0 Na Mg 22.99 24.31 0.9 19 1.2 20 K Ca 39.10 40.08 0.8 37 1.0 38 Rb Sr 85.47 87.62 0.8 55 0.9 56 Cs Ba 132.9 137.3 0.7 87 0.9 88 Fr Ra (223) 226.0 * Lanthanide Series † Actinide Series 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69 63.55 65.39 69.72 72.61 74.92 78.96 79.90 1.8 1.8 2.0 2.4 2.8 39 Y 88.91 40 Zr 91.22 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 92.91 95.94 (99) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 1.7 1.8 1.9 2.1 2.5 81 Tl 82 Pb 83 Bi 84 Po 85 At 204.4 207.2 209.0 (209) (210) 1.8 1.9 1.9 2.0 2.2 68 69 70 71 57 La 72 Hf 73 Ta 138.9 178.5 180.9 * 89 Ac † 227.0 58 104 105 74 75 76 77 78 W Re Os Ir Pt 183.9 186.2 190.2 192.2 195.1 197.0 200.6 106 107 108 109 65 66 67 Rf Db Sg Bh Hs Mt (261) (262) (263) (262) (265) (268) 59 60 61 62 63 64 Ce Pr 140.1 140.9 79 80 Au Hg Nd Pm Sm Eu Gd Tb Dy Ho 144.2 90 91 92 Th Pa U 232.0 231.0 238.0 (145) 150.4 152.0 157.3 158.9 93 94 95 96 97 162.5 Er Tm Yb Lu 164.9 167.3 168.9 173.0 175.0 100 101 102 103 98 99 Np Pu Am Cm Bk Cf Es Fm Md No Lr 237.0 (251) (252) (260) (244) HONClBrIF (243) (247) (247) (257) (258) (259) 18 Ar 39.95 36 Kr 83.80 54 Xe 131.3 86 Rn (222) 1. 2. 3. (2 pts) Which of the following changes is/are endothermic for the underlined object? i. baking a potato ii. a person being burned by a pan iii. a wood log burning iv. a lit light bulb shining v. a person digesting food A. iii only B. iii and iv C. iii and iv D. i and iv E. i and ii (2 pts) Which of the following are elements? i. KOH ii. Ne iii. CO iv. carbon tetrachloride v. calcium A. i, ii, and iii B. iv and v C. ii and iii D. ii and v E. ii, iii, and v (2 pts) Which of the following correctly matches each sample with its classification as either macroscopic, microscopic, or particulate? A. B. C. D. E. 4. Macroscopic protein molecule protein molecule crystal on polished metal cat hair cat hair Microscopic cat hair crystal on polished metal cat hair crystal on polished metal protein molecule Particulate crystal on polished metal cat hair protein molecule protein molecule crystal on polished metal (2 pts) Which of the following is not a particulate sample of matter? A. B. C. An oxygen molecule A human egg cell An electron D. E. A nickel atom A hemoglobin molecule ____/8 5. A chemistry instructor puts some Iodine crystals (I2 (s)) in a flask. Upon warming the flask, a purple cloud appears. a. (5 pts) Write the chemical equation that describes this process. b. (5 pts) Later, an ice cube was held next to the top edge of the flask. What happened? c. (5 pts) Write the equation for the process from (b). d. (5 pts) Which of the processes was endothermic for the Iodine? Briefly describe why. I did this demonstration with a different apparatus last quarter – this time it was the U-shaped tube. Ice Purple Cloud I2 ____/20 6. 7. 8. 9. (2 pts) Which of the following properties is/are classified as physical? i. ii. iii. iv. v. the odor of glass cleaning solution the color of chlorine gas the electrical conductivity of copper wire the ability of milk to sour a compound does not react with bromine A. B. C. i only ii only i and ii D. E. i, ii, and iii iv and v (2 pts) Which of the following properties is/are classified as chemical? i. ii. iii. iv. v. the taste of honey the ability of hair to stretch the corrosive character of hydrochloric acid the combustibility of ethanol the softness of talc A. B. C. i and ii i, ii, and v iii only D. E. iv only iii and iv (2 pts) Which of the following substances is/are homogeneous? i. ii. iii. mineral oil a plant leaf sausage iv. v. sugar freshly squeezed lemonade A. B. C. i only ii only iv only D. E. i and iv i, ii, and iv (2 pts) In which of the following pairs of substances will there be a net attractive electrostatic force? A. B. C. D. E. Two positively charged table tennis balls A negatively charged piece of dust and a positively charged piece of dust A positively charged sodium ion and a positively charged potassium ion A negatively charged chloride ion and a negatively charged bromide ion Two negatively charged pith balls ____/8 10. (2 pts) One of the main features of Dalton's atomic theory which is no longer considered valid is: All atoms of each element are identical in every respect. Which of the following is the best explanation of why this feature is no longer considered valid? A. B. C. D. E. The existence of isotopes Mass is conserved in a chemical change Nearly all of the mass of an atom is concentrated in the nucleus The total charge of the electrons of an atom exactly balances the positive charge of the nucleus The planetary model of the atom has been shown to be incorrect 11. (2 pts) Which of the three major subatomic particles has/have a charge of +1? 12. 41 K (2 pts) The nuclear symbol of an isotope of potassium is 19 . Indicate the number of protons, number of neutrons, atomic number, and mass number of the isotope. A. B. C. D. E. Number of protons 19 22 19 41 41 Number of neutrons 22 19 41 19 19 Atomic number 19 41 19 22 41 Mass number 41 19 22 19 22 13. (2 pts) Which of the three major subatomic particles has/have a mass of approximately one amu? 14. (3 pts) Isotopes of an element vary in mass because of differing numbers of: ____/11 15. (5 pts) Write the elemental formula for the following elements: Element i. nitrogen ii. sulfur iii. lithium iv. bromine v. oxygen Elemental Formula 16. (3 pts). The alkali metal kalium was discovered in 1807. What is its English name and symbol? 17. (10 pts) Neatly sketch and label the apparatus/experiment that disproved the Plum Pudding model of the atom. ____/18 18. The element bromine (name for the Greek word for stench, brômos) was discovered in 1826 by Antoine J. Balard. a. (3 pts). Write its electronic configuration. On the figure below: b. (3 pts). Label the s, p, and d orbitals. c. (2 pts). Fill in electrons for Bromine in the energy level diagram. E d. (2 pts). Bromine has two stable isotope with masses 79 and 81. Write the nuclear symbol for these isotopes. ____/10 19. Early chemists classified the elements by their chemical properties and gave these groups of elements special names. a. (3 pts) What feature of the periodic table do these groups correspond to? b. (3 pts) Write the names of three of these groups. c. (0 pts) Choose one of the following elements and circle it. (Read d – f before making your choice!) Calcium Cobalt Chlorine d. (3 pts) Write the electronic configuration of that element: e. (3 pts) Write the name of the group that the element belongs to: f. (2 pts) How many electrons are your element’s valence (outer shell)? ____/12 20. (7 pts) Express the following numbers in scientific notation (use your calculator for calculations). Number Scientific Notation 0.0821 1024.2 1000 50.2 a million 3.14159 × 0.0005 ( 6.02 × 1023 ) ÷ ( 1,000,000,000 ) Problem #20 is part of Unit C – we won’t get to this section before the exam. 21. (6 pts) A dedicated Chemistry 100 student tried to repeat the paper chromatography experiment from lecture. Based on the individual results, Label each of the following samples as homogenous, heterogeneous, or undetermined. Sample: Fluid: Black Sharpie Water Black Marker (Permanent) Rubbing Alcohol Blue Overhead Pen Water Resulting Paper: Sample Type: (homogenous/ heterogeneous/ undetermined) ____/13