Useful Information for Academic Challenge Chemistry Exam K = C T f = k f m

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Ferdinand Clark
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1 Useful Information for Academic Challenge Chemistry Exam ph = -log [H + ] P 1 V 1 /T 1 = P 2 V 2 /T 2 PV = nrt (R = L atm mol -1 K -1 ) K = C Heat capacity t = heat energy effusion rate 1 / d (P & T are constant) T f = k f m Chemistry (S) - 1

2 1. The atomic weights and abundances for three isotopes of an element are given in the table. From this data, what is the atomic weight of the element? % abundance atomic weight amu amu amu a amu b amu c amu d amu e amu 2. For the following reaction, what will cause a shift in equilibrium to the left? C 2 H 6(g) + heat H 2(g) + C 2 H 4(g) a. lowering of the temperature b. addition of a catalyst c. decreasing the concentration of H 2(g) d. increasing the volume of the system e. removal of C 2 H 4 (g) from the system 3. Which hydrate will lose the greatest mass of water from a 1.0 gram sample? a. CoCl 2 6H 2 O b. CrCl 3 5H 2 O c. CuSO 4 5H 2 O d. CaSO 4 2H 2 O e. BaCl 2 2H 2 O 4. Which substance is more soluble in carbon tetrachloride than water? a. CH 3 OH b. HCl c. NaOH d. I 2 e. AgNO 3 5. What is the maximum number of grams of Au(OH) 3 that can be formed from g of KAuCl 4 and g of Na 2 CO 3 in the following reaction? 2KAuCl 4 + 3Na 2 CO 3 + 3H 2 O 2Au(OH) 3 + 6NaCl + 2KCl + 3CO 2 a g b g c g d g e g g of sucrose (C 12 H 22 O 11 ) are burned in a calorimeter in the presence of excess oxygen. The heat capacity of the calorimeter was previously found to be 9.00 kj o C -1. The combustion caused the temperature of the substance to change from to o C. What is the heat of combustion per mole of sucrose? a x 10 3 kjmol -1 b x 10 2 kjmol -1 c x 10 0 kjmol -1 d x 10 0 kjmol -1 e x 10 3 kjmol Given the following equations, Fe 2 O 3(s) + 3CO(g) 2Fe(s) + 3CO 2(g) H o = kj CO(g) + 1/2O 2(g) CO 2(g) H o = kj Calculate H o for the reaction: 2Fe(s) + 3/2O 2(g) Fe 2 O 3(s) a kj b kj c kj d kj e kj Chemistry (S) - 2

3 8. A substance has a density of 9.32 lb/gal. The density of water is 8.34 lb/gal. Calculate the specific gravity of the substance. a b c d e Which group below correctly underlines the largest atom or ion in the group? a. O, O 2-, S 2-, S b. Cr 2+, Cr, Cr 3+ c. Ge, Te, Se, Sn d. Ga, F, Br, C e. F, F -, N, Sr 10. Which group below correctly underlines the element with the largest ionization energy? a. C, B, Al, Si b. Be, Rb, Ca, Ba c. As, F, N, Br d. Fr, Co, P, F e. Bi, Sb, As, N 11. Given the electronegativities H=2.1, Br=2.8, F=4.0, Cl=2.9, C=2.5, and I=2.2, in which list are the bonds arranged correctly according to increasing polarity (least polar to most polar). a. H-I, H-Cl, H-Br, H-F b. C-Cl, H-F, H-I, H-Cl c. H-F, H-Cl, H-Br, H-I d. H-I, C-Cl, H-Cl, H-F e. H-Cl, H-F, C-Cl, H-I 12. Using Graham's Law, determine which gas listed below will effuse most rapidly. NH 3 HCl HF HBr HI a. NH 3 b. HCl c. HF d. HBr e. HI 13. A compound contains g of carbon, g of hydrogen, g of nitrogen, and g of oxygen. What is the empirical formula of the compound? a. C 2 HN 2 O 2 b. CH 3 NO c. CH 3 NO 2 d. CH 2 NO 3 e. CHNO 14. Which molecular shape is correct? a. XeF 4 / tetrahedral b. SF 6 / octahedral c. BCl 3 / T-shaped d. PF 3 / trigonal planar e. HgBr 2 / angular g of C 2 H 5 OH are dissolved in 820g of acid. The freezing point of this solution is 9.25 o C. The freezing point of the original acid is o C. What is the molal freezing point depression constant, K f, of the acid? a o C/m b o C/m c o C/m d o C/m e o C/m Chemistry (S) - 3

4 16. What is the final pressure of a gas if 5.34 L at 754 torr and 28 o C is expanded to 7.82 L at 92 o C? a torr b torr c. 624 torr d. 424 torr e. 911 torr 17. Which of the following contains the largest number of nitrogen atoms? a L N 2 at STP b..2 L of 5.00 M NH 3 c mol NH 4 Cl d x molecules NO e. all of the above contain the same number of N atoms 18. The correct coefficients when balancing the oxidation reduction reaction below are 20. Given the information below: Sn e - Sn 2+ NO H + + 3e - NO + 2H 2 O E o = 0.96 V E o = 0.15 V What would be the E o cell value when nitrate ions oxidize Tin(II) ions? a. 111 V b V c V d V e V 21. Which set of products correctly completes the following nuclear equation? 14 7 N + 4 2He a F + e - MnO I - + H + I 2 + Mn 2+ + H 2 O a. 1,2,8,1,1,4 b. 1,2,2,1,1,4 c. 2,20,8,14,4,16 d. 2,10,16,5,2,8 e. 1,1,1,1,1,2 b. c. d. e. 1 n F 10 5 B 16 8 O + e O + 1 1H 19. Which statement is correct for the following cell? Zn Zn 2+ (1.0 M) Cu 2+ (1.0 M) Cu a. Zn 2+ concentration will increase b. Cu electrode mass will decrease c. electrons flow from Cu electrode to Zn electrode d. Zn electrode mass will increase e. oxidation occurs at Cu electrode 22. Based upon the table of information, which statement correctly explains why HI is a stronger acid than HCl? HCl HI bond energy (kcal) % ionic character 12 5 dipole (debyes) bond length (Å) a. HI has a lower bond energy than HCl. b. HI has a lower percentage of ionic character than HCl. c. HCl has a stronger dipole moment than HI. Chemistry (S) - 4

5 d. Iodine is heavier than chlorine e. None of the data supports the conclusion that HI is a stronger acid than HCl Chemistry (S) - 5

6 23. The titration curve depicts the titration of a d. liquids in gases e. All of the above a. strong acid with a strong base b. weak base with a strong acid c. weak acid with a strong base d. all acids and bases e. none of the above 24. Which statement about titrations is correct? a. Phenolphthalein indicator changes from yellow to red. b. A selected indicator displays a color change at the endpoint of the titration. c. All titration curves have the same shape. d. The concentration of an acid but not a base can be determined from a titration. e. None of the above. 25. Which of the following may form a colloidal dispersion? a. gases in liquids b. gases in solids c. liquids in solids Chemistry (S) - 6

7 26. Which formula does not match the compound's organic name? a. CH 3 CH 2 NH 2 ethylamine b. CH 3 CH 2 CHO propionaldehyde c. CH 3 COCH 2 CH 3 butanone d. C 6 C 5 Br bromobenzene e. C 6 C 5 C CH acetylene a. HO - 2 /H 2 O 2 b. NH - 2 /NH 3 c. H 2 PO - 4 /H 3 PO 4 d. SO 2-4 /H 2 SO 4 e. + NH 3 /NH Which of the following list all of the structural isomers below? Only the carbon skeletons of each molecule are drawn. C-C-C-C-C C-C-C-C-C C C I II C C-C-C-C-C C-C-C-C C C III IV a. I, II b. II, III c. III, IV d. I, II, III, IV e. I, II, IV 28. Which formula/name is correct? a. CoCO 3 / cobalt (II) carbonate b. HgCl 2 / mercury (I) chloride c. SF 6 / sulfur heptafluoride d. PBr 3 / phosphorus bromide e. (NH 4 ) 2 SO 3 / ammonium sulfate 29. Which set of Bronsted base/conjugate acid is incorrect? Chemistry (S) - 7

8 30. A compound called isoprene is used to produce a dimer called dipentene. Given the following data, what is the rate law for this reaction? Initial conc. Initial rate isoprene of formation (mol L -1 ) dipentene (mol L -1 s -1 ) a. rate = k[dipentene] 4 b. rate = k[isoprene] 2 c. rate = k[isoprene] d. rate = k[isoprene][dipentene] e. rate = k[isoprene] A compound contains 0.193g C; g H; 0.112g N; 0.149g P; and 0.334g O. What is the empirical formula of this compound? a. C 10 H 16 N 5 P 3 O 13 b. C 3 H 5 N 2 P 1 O 4 c. CHNPO d. C 2 HNPO 3 e. CH 3 NPO What is the nuclear composition of 85 Rb? a. 37 neutrons, 85 protons b. 48 protons, 48 electrons c. 48 neutrons, 37 protons d. 37 protons, 48 electrons e. 37 protons, 37 neutrons 33. Which electronic configuration does not match the element or ion it is paired with? a. Sm [Xe]6s 2 4f 6 b. Bi [Xe]6s 2 4f 14 5d 10 6p 3 c. In [Kr]5s 2 4d 10 5p 1 d. Bk [Rn]7s 2 5f 8 e. Cl - [Ne]3s 2 3p 6 or [Ar] 34. Which of the following correctly identifies the type of hybrid orbital of the underlined atom in each compound? a. XeF 6 sp 3 d 2 b. CH 4 sp 2 c. HgBr 2 sp 2 d. AsCl 5 sp 3 e. H 2 O sp What is the ph of a 3.5 x 10-8 M acid solution? a. 3.5 b. 7.5 c. 4.0 d. 8.0 e In the analytical lab procedures for identifying Hg 2 2+, Ag +, and Pb 2+ cations in a solution, a quantity of HCl is added to an unknown solution. If a white precipitate forms, we can conclude that: a. all three ions may be present in the white chloride precipitate b. the silver ion is present. c. the lead ion is present. d. the mercury ion is present. e. none of the ions are present. 37. Flame tests are used to identify various cations. Which cation/flame color listed below is incorrect? a. Ba 2+ green b. Sr 2+ crimson c. K + violet d. Ca 2+ brick-red e. Na + blue 38. What type of chemical reaction is shown below? 2HgO(s) 2Hg(l) + O 2(g) a. decomposition b. displacement Chemistry (S) - 8

9 c. metathesis d. acid/base e. none of the above Chemistry (S) - 9

10 39. How many grams of methane are required to react with 115 g of oxygen? The chemical reaction is: CH 4 + 2O 2 CO 2 + 2H 2 O a g b g c. 115 g d g e g 40. What is the volume of concentrated sulfuric acid which is necessary to prepare 1.00 L of a M solution. Concentrated sulfuric acid has a molarity of a ml b ml c. 100 ml d. 115 ml e..115 ml Chemistry (S) - 10

11 ANSWER KEY 1. B 2. A 3. A 4. D 5. E 6. E 7. C 8. B 9. C 10. A 11. D 12. A 13. E 14. B 15. C 16. C 17. A 18. D 19. A 20. B 21. E 22. A 23. C 24. B 25. E 26. E 27. E 28. A 29. D 30. B 31. A 32. C 33. D 34. A 35. B 36. A 37. E 38. A 39. A 40. A Chemistry (S) - 11

Multiple Choice. Multiple Choice

Multiple Choice. Multiple Choice 1. At what temperature in degree Celcius is the value in degree Fahrenheit twice of that in degree Celcius? A) 160 o C B) -24.6 o C C) 6.4 o C D) 22.2 o C E) 32 o C 2. The correct name for NaOCl is, A)