CHEM 1301 POSSIBLE EXTRAS REVIEW. 1. IONIC all ionic compounds have IONIC intermolecular forces

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1 CHEM 1301 POSSIBLE EXTRAS REVIEW Chapter Ten Stuff Differences between solids, liquids and gases. Intermolecular Forces important in solid state Stronger they are, higher the melting and boiling points: 1. IONIC all ionic compounds have IONIC intermolecular forces 2. METALLIC all metals have METALLIC intermolecular forces Both of these are infinite networks go on and on and on COVALENT molecules have: 3. HYDROGEN BONDS for H attached to F, O, N (or Cl) 4. DIPOLE-DIPOLE if the molecule is polar [has a dipole opposite ends] 5. LONDON DISPERSON if the molecule is not polar. i. e., has no polar bonds or the polar bonds cancel out. Typical questions: For each of the following solids, assign whether the intermolecular forces are (A) ionic (B) metallic (C) hydrogen bonding (D) dipole-dipole (E) London dispersion 1. NaCl 2. Cl 2 3. Hg 4. Fe 5. H 2 O 6. NH 3 7. FBr 8. CO 2 9. KBr 10. CH Which of the following would be expected to have the highest boiling point? (A) NaCl (B) Na (C) Cl 2 (D) all the same (E) can t tell 12. Which substance has the highest boiling point? (A) CH4 (B) He (C) HF (D) Cl2 13. Which group of substances is arranged in order from the highest to the lowest melting point? (A) HF>H2>NaF (B) NaF>H2>HF (C) HF>NaF>H2 (D) NaF>HF>H2 1

2 14. Arrange KCl, NH3, and CH4 in order of increasing boiling point. (A) CH4<KCl<NH3 (B) NH3<KCl<CH4 (C) CH4<NH3<KCl (D) NH3<CH4<KCl 15. Which has the highest melting point? (A) S8 (B) H2O (C) Ar (D) BaF2 16. Which of the following molecules will not form hydrogen bonds? O (A) H 3 C CH 2 C OH (B) HF O H (C) H 3 C CH 2 C CH 3 (D) H 3 C CH 2 N CH In hydrogen iodide are the most important intermolecular forces. (A) dipole-dipole forces (B) London dispersion forces (C) hydrogen bonding (D) ionic GASES Pressure measured in atmospheres or mmhg [1 atm = 760 mm Hg] Temperature measured in Kelvin [K = C + 273] Volume measured in liters n moles Pressure is proportional to temperature and number of moles and inversely proportional to volume Put together the relationships using the correct units: PV = nrt [R = l atm / mol K] 18. When the temperature in Kelvin of a fixed quantity of an ideal gas is quadrupled and the pressure is doubled, what is the net effect on the volume of the gas? (A) The volume remains constant. (B) The volume increases two fold. (C) The volume increases four fold. (D) The volume increases eight fold. 2

3 19. Air is sealed in a vessel at 273 C and then cooled to 0 C. If the vessel itself does not contract, the pressure inside the vessel will become (A) twice its original value. (B) none of these. (C) zero. (D) one-fourth of its original value. (E) one-half of its original value. 20. Both the pressure and the absolute temperature of a certain gas sample are doubled. In the absence of dissociation, the volume of the gas is (A) quadrupled. (B) decreased by one fourth. (C) doubled. (D) decreased by one half. (E) unchanged. 21. If a gas at 1 atm and 273 K occupies 3.36 L, how many moles does it contain? (A) 0.15 (B) 0.81 (C) 3.4 (D) A gas sample occupies a volume of 16.4 L at 27 C and atm. How many moles of gas are present? (A) (B) (C) 3.50 (D) What is the volume of 2.00 mol of helium gas at 27 C and 3.00 atm? (A) 6.1 x 10 2 L (B) 16.4 L (C) 1.48 L (D) 44.8 L 24. How many moles of gas are in a sample with a volume of 500 ml at 25 C and atm? (A) mol (B) 10.2 mol (C) mol (D) 13.4 mol This can be combined into the Roadmap: grams of A g grams of B g Particles N A N = 6.02 x n n = g / MM Particles N B N = 6.02 x n Moles of A n A Moles of B n B Volume of Gas, V at Temp, T, and Pressure, P pv = nrt n B = (b/a)n A M = n / L pv = nrt Volume of Gas, V at Temp, T, and Pressure, P Volume of Solution, L Volume of Solution, L 3

4 25. What is the number of molecules in 1.00 ml of an ideal gas at 1 atm and 273 K? (A) 2.69 x (B) 2.69 x (C) 6.02 x (D) 2.24 x How many grams of CO2 would occupy an 8.8 L flask at 300 K and 1.1 atm? (A) 14 g (B) 17 g (C) 22 g (D) 32 g 27. What volume will 5.10 g of sulfuryl fluoride, SO2F2, occupy at 1 atm and 273 K? (A) L (B) 1.12 L (C) 2.24 L (D) 11.2 L (E) 22.4 L 28. What volume does g of oxygen gas (O 2 ) occupy at 546 C and 2.00 atm? (A) 5.6 L (B) 11.2 L (C) 22.4 L (D) 67.2 L (E) 16.8 L 29. When 18.0 g of water is heated to steam at 100 C, the volume at 1 atm pressure is approximately?: (A) 13.2 ml (B) 18.6 L (C) 1800 ml (D) 11 L (E) 30.6 L 30. Benzene, C 6 H 6, can be burned in oxygen according to the equation:, 2C 6 H 6 (l) + 15O 2 (g) 12CO 2 (g) + 6H 2 O(g). If 5.0 L of oxygen measured at 1 atm and 273 K were required to burn a given amount of benzene, the 1 atm and 273 K volume of CO 2 formed would be (A) 17.9 L (B) 4 L (C) 33.4 (D) 5.5 L 31. What mass of CaCO 3 will produce 8.0 L of CO 2 (measured at 1 atm and 273 K) in the reaction, CaCO 3 (s) CaO(s) + CO 2 (g)? (A) 4.46 g (B) 12.5 g (C) 35.7 g (D) 280 g 32. How many liters of CO 2 gas at 1 atm and 273 K can be obtained by completely burning one mole of C 3 H 8? C 3 H 8 (g) + O 2 (g) CO 2 (g) + H 2 O(g) (A) 11.2 (B) 44.8 (C) 67.2 (D) What volume of pure N 2 O at 1 atm and 273 K could be prepared by the controlled decomposition of 8.00 g of ammonium nitrate - NH 4 NO 3 (s) N 2 O(g) + 2H 2 O(l) (A) 1.12 L (B) 2.24 L (C) 3.36 L (D) 4.48 L 4

5 34. How many liters of hydrogen gas with an excess of nitrogen at 1 atm and 273 K are required to prepare 45.0 g of ammonia? 3 H 2 (g) + N 2 (g) 2 NH 3 (g) (A) 39.5 (B) 30.0 (C) 59.3 (D) How many liters of hydrogen at 1 atm and 273 K can be produced by the reaction of 9.00 g of Al with excess dilute H 2 SO 4 : 2Al(s) + 3H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (aq) + 3H 2 (g) (A) 5.61 L (B) 11.2 L (C) 33.6 L (D) 67.2 L More Reactions We started talking about REDOX equations. You need to be able to: a) assign oxidation numbers: b) look at an equation and say whether it is a redox equation by change in charge or oxidation number c) if redox, which atom is reduced and which is oxidized 36. Calculate the oxidation number of the chlorine in perchloric acid, HClO 4, a strong acid. (A) -1 (B) +4 (C) +5 (D) Calculate the oxidation number of sulfur in sodium metabisulfite, Na 2 S 2 O 5. (A) -2 (B) +2 (C) +4 (D) Sodium tripolyphosphate is used in detergents to make them effective in hard water. Calculate the oxidation number of phosphorus in Na 5 P 3 O 10. (A) +3 (B) +5 (C) +10 (D) Calculate the oxidation number of iodine in I 2. (A) -1 (B) 0 (C) +1 (D) The oxidation numbers of P, S and Cl in H 2 PO 2 -, H 2 S and KClO 4 are, respectively (A) -1, -1, +3 (B) +1, -2, +7 (C) +1, +2, +7 (D) -1, -2, +7 (E) -1, -2, Identify which species is reduced in the following redox reaction. Hg 2+ (aq) + Cu(s) Cu 2+ (aq) + Hg(l) (A) Hg 2+ (aq) (B) Cu(s) (C) Cu 2+ (aq) (D) Hg(l) 5

6 42. Sodium thiosulfate, Na 2 S 2 O 3, is used as a fixer in black and white photography. Identify which atom is oxidized in the reaction of thiosulfate with iodine. 2S 2 O 3 2- (aq) + I 2 (aq) S 4 O 6 2- (aq) + 2I - (aq) (A) I (B) I - (C) S (D) O 43. Which one of the following is not a redox reaction? (A) 2H 2 (g) + O 2 (g) 2H 2 O(l) (B) Zn(s) + H 2 SO 4 (aq) ZnSO 4 (aq) + H 2 (g) (C) H 2 O(l) + NH 3 (g) NH 4 + (aq) + OH - (aq) (D) 6FeSO 4 (aq) + K 2 Cr 2 O 7 (aq) + 7H 2 SO 4 (aq) Cr 2 (SO 4 ) 3 (aq) + 3Fe 2 (SO 4 ) 3 (aq) + K 2 SO 4 (aq) + 7H 2 O(l) (E) Cl 2 (g) + 2KBr(aq) Br 2 (l) + 2KCl(aq) 44. Which one of the following is not a redox reaction? (A) 2H 2 O 2 (aq) 2H 2 O(l) + O 2 (g) (B) N 2 (g) + 3H 2 (g) 2NH 3 (g) (C) BaCl 2 (aq) + K 2 CrO 4 (aq) BaCrO 4 (aq) + 2KCl(aq) (D) 2Al(s) + Fe 2 O 3 (s) Al 2 O 3 (s) + 2Fe(s) (E) 2H 2 O(g) 2H 2 (g) + O 2 (g) 45. Which one of the following is a redox reaction? (A) (B) (C) (D) (E) 2Na(g) + Cl 2 (g) 2NaCl(s) Ba 2+ (aq) + SO 2-4 (aq) BaSO 4 (s) K 2 Cr 2 O 7 (aq) + 2KOH(aq) 2K 2 CrO 4 (aq) + H 2 O(l) Na 2 CO 3 (s) + 2HCl(aq) 2NaCl(aq) + CO 2 (g) + H 2 O(l) H 2 O(l) H + (aq) + OH - (aq) 46. Which one of the following is not a redox reaction? (A) 2Na(s) + 2H 2 O(l) 2NaOH(aq) + H 2 (g) (B) H 2 (g) + Cl 2 (g) 2HCl(g) (C) 2H 2 O 2 (aq) 2H 2 O(l) + O 2 (g) (D) Fe 2 O 3 (s) + 3H 2 SO 4 (aq) Fe 2 (SO 4 ) 3 (aq) + 3H 2 O(l) (E) 2KMnO 4 (aq) + 10FeSO 4 (aq) + 8H 2 SO 4 (aq) K 2 SO 4 (aq) + 2MnSO 4 (aq) + 5Fe 2 (SO 4 ) 3 (aq) + 8H 2 O(l) We discussed the relative strength of metals and getting electricity from redox reactions. 6

7 Acids and Bases a) Arrhenius definition b) Bronsted-Lowry definition c) strong and weak d) neutralization e) ph = -log [H + ] or log [H 3 O + ] 47. Which of the following is a weak acid? (A) H 2 SO 4 (B) HNO 3 (C) HF (D) HBr 48. Which of the following is a strong acid? (A) H 3 PO 4 (B) HNO 3 (C) HF (D) CH 3 COOH 49. Which of the following is a strong base? (A) NH 3 (B) Ba(OH) 2 (C) Al(OH) 3 (D) B(OH) Which of the following is a weak base? (A) NH 3 (B) Sr(OH) 2 (C) Ba(OH) 2 (D) NaOH 51. Which one of the following substances is a strong acid? (A) HNO 3 (B) H 2 CO 3 (C) NH 3 (D) CH 3 COOH (E) H 3 PO What is the ph of a 0.75 M HNO 3 solution? (A) 0.12 (B) 0.29 (C) 0.63 (D) What is the ph of a M HClO 4 solution? (A) (B) (C) (D) What is the ph of a M HBr solution? (A) 0.89 (B) 1.12 (C) 1.30 (D) 3.00 Answers: 1 30: A E B B C C D E A E A C D C D C A B E E A A B A B B B E E B 31-54: C C B D B D C B B B A C C C A D C B B A A A C C 7