chm2045 exam 1 fall05 key

chm2045 exam 1 fall05 key - CHM-32945 ~ r-~Sept‘-20 20,05...

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Unformatted text preview: CHM-32945 ~ r. .. -~Sept‘.-20, 20,05 _ Please bubblednAastheTest Form Code atythe to}; right of your answer sheet. Failure to dothis will result in a penalty of 10. points. ' 1. Rutherford’s a—particle irradiation experiment on atomic structure supported/each of the "’*foflowingconclusions'except that ~ ~ "W V ’ , protons reside in the nucleus ' " ' (3) electrons are essentially massless ' (4) atoms are mainly empty Space (5) atoms have a nonuniform distribution of mass. ' " 2. Which of the follOwing listed pairs 0f atoms have the same numberrof‘neutrons?” (1) 63Cu and 64le (2) °°Ni and-°3Cu- 7 (3) 764Ni and 64211 ’(4) 64Zn and 68Zn (‘5‘) "63Cu ‘and 68211. . ’ *5 , ' 3. Pennies minted after 1983 are composed of 97% Zn and 3.0% Cu and have'a mass of 2.46 g. _ Based. onthis information,,the amount of Cu in a pennyis closestto ’ (1) (2) 0.014 mol (3) 0.038 mol. (4) 0.040 mol (5) 0.27 mol. .4. . Thenumberofmagnesium ions contained in one mL of 0.184 M magnesium bromide solution is closest to , ‘ W w (1) 6.02 x 10:: (2) 2.22 x 1020 (3) 1.11 x 1023 (4) 1,1] x 1020 5 2.22 x 10 . ~ ' _ . "5. *‘The~mass%bxygenrincepper (II) formate‘tetrahydrate,Cu(H.C02)2-4H20. is closest to I _(1) 41.67% (2) 10.64% (3) 83.34% (4) 28.36% '(5)_56'.13_%_. 6. In olive Oil, 5. recommended vegetable oil for human consumption, the main fatty. acid is oleic acid, C18H3402, for which A gqmb = ——1.11 x 1’0“1 kJ/mol. Thus, if in combusting oleic acid, ~ H20(g) (rather than H20(l)) is formed, AHf" for oleic acid is closest to (1) 94 kJ/mol (2) 845 kJ/mol (3) .-845 kJ/mol , (4) -8130 kJ/mol (5) 7. Given that the correct formula for sodium sulfate is Na2804, the correct formula for chromium(III) sulfate is . CI‘2SO4 8. If burning 1.000 g of kerosene liberates 11.00 kcal, burning 0.2500 g of kerosene can raise the temperature, T, of a 75.00 mL sample of water initially at 25.0 °C to a final T thatlis closest to (1) 620°C (2) 46.0 °C (3) 45.6 °C (4) 45.62 °C (5) 25.0 °C. _onewmvole of butanol, {C4H90H, is completely combusted by reaction with atmospheric oxygen, the tbta‘l moieg“'6r"'rhbleeulé‘s'pr‘oduéed " “ l "i"ii“’tifiifif’:i::_§;: " (1).5 (2) 8 , (3) 6 (4)—9... (5) 11- 10. Phosphorus, P, reacts with chlorine, C12, to give a gaseous compound of the formula, PClz. Therefore, if 2.097 g P reacts to yield 9.298 g of the compound, the value for x is (1) 2 (21.1 (3) 4 (4) 5 (5) 6- f 11. If 2.00 g of X (a mythical element) reacts With 5.00 g of Z (another mythical element) to ‘" f‘prod’uee 7.00 g of a compoundwhiclrhasrtheformula X3Z4, arrd‘theatomicnnassn)f%is 135.0 u, the atomic mass of X is (1) 39.511 (2) 105u (3) 72.0u (4) 89.5113. (5) 42.0 11. 12. Bromine consists of two naturally-occurring isotopes. “If one of‘these/‘isotopes'has a mass of 78.918 11 and is 50.54% abundant, the Other isotope has a mass which is closest to . (1). 79.82.11 (21.19.97.111-13);80.91 u .._;(4),,,81-.9§_.11;._ 13. Consider: PC1-3(g) + 012(g) ——+~-PC.15(g). If 119.37g B015 (208.2 'g/mol) is produced when 61.3 g C12 (70.91 g/mol) reacts in excess P013, the percent yield for the‘reaotion is closest to (1) 85.0%” {(2) 55.3% it 1(3)7751_.4% (4) 43.7% (5) 57.3%. 14. The volume of 0.1107 M KCl which contains 15.00 g of dissolved KCl isclosest. to ,,.(1)_~:;5.02227 1:551: **f‘”***(1)ii1~.~§~1§ ;, "(5)5 ‘ 15. If 30.5 mL of 1.50 M K201‘207 is added to a 250-mL volumetric flask and diluted to the mark- with thorough mixing, the potassium iOn concentration, [K+], in, the resulting solution will be closest to (1) 0.180 M (2), 0.3’60M I (3) 1.50M (4)5.00M (5) 12.5 M. _, ‘ 16. When 14.2 g KBr is dissolved in 100.0 g of water in a coffee-cup calorimeter, the temperature 7 drops from28.88 °C to 23.38 °C. If the solution has a specific heat capacity which is essentially the same as H200), the enthalpy change per gram 0f KBr dissolved is closest to (1)2816 J—,Lg— "203 1,13»..- (3) 2320.1/g (4) 2.63 XJOSJ/g. (5,) 185 Mg, 17. Ammonia gas (NH3) reacts with oxygen in the air to produce NO(g) and H200). Based on this, the maximum mass of NO(g) which can be produced from a reaction mixture of 1.00 mol each of ammonia and oxygen is clOsest to ~ ' ‘ (1) 30.0g (2) 24.0g (3)_17.0g (4) 37.5g » (5) 48.0 g. 18. For the hydrogendichromate ion, HOCr205‘, the oxidation number fer. Cr is (1) +2 (2) +4 (3) +6 (4) +8 (5) -3. ‘ 19. For: 2 Fe(s)'+ 6 H200) ———> 2 Fe(OH)3(s) + 3 H2(g), AH,‘ = 321.8 kJ. For: Fe203(s) + 3 H200) ——> 2 Fe(OH)3(s), AH1r = 288.6 kJ. For: 2 H200) —2 2 H2(g) + 02(g), AHr = 571.7 kJ. Based on these data, for: 4 Fe(s) + 3 02 (g) ———> 2 Fe203(s), AHr is closest to (1) -1650 kJ (2) —1182kJ (3) 505.3 M (4) 360.5]kJ (5) 1447 kJ. 20. If 47.7 mL of 36.0% HCl solution (with d = 1.18 ‘iS‘diluted'with water to a volume of 1.50 L, the concentration of the diluted solution is closest to - (1) 1.23M’ (2) 7.45M '(3) 0.370M (4) 0.785M (5) 0.0234 M. ...
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This note was uploaded on 04/24/2008 for the course CHM 2045 taught by Professor Mitchell during the Spring '07 term at University of Florida.

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chm2045 exam 1 fall05 key - CHM-32945 ~ r-~Sept‘-20 20,05...

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