a) The molecule has a trigonal pyramidal geometry. b) The molecule is nonpolar

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1 1. Which of these bonds is the most polar? a) C N b) Br Cl c) F - F d) O O e) O - C 2. SCl 2, a cherry-red liquid, is the simplest sulfur chloride and one of the most common. Draw the Lewis structure for SCl 2 and apply the VSEPR theory to determine which of the following statements is correct for this molecule. 4 VSEPR groups bent geometry a) There is one pair of nonbonding electrons on the central atom. b) The molecule has a bond angle of about o. c) The molecule is linear. d) The molecule has one double bond. e) There are several resonance structures for this molecule. 3. Draw the Lewis structure for NCl 3 and apply the VSEPR theory to determine which of the following statements is correct for this molecule... a) The molecule has a trigonal pyramidal geometry. b) The molecule is nonpolar c) The molecule has identical bond angles of 120 o. d) There are several resonance structures for this molecule. e) The central atom contains no lone pairs of electrons. 4 VSEPR groups There are 3 lone pairs on each Cl atom, which are not shown here. 4. Draw the Lewis structure for CCl 4 and apply the VSEPR theory to determine which of the following statements is correct for this molecule. The molecule has 4 polar bonds but due to tetrahedral geometry, the polarities all cancel. a) The molecule has a trigonal pyramidal geometry. b) The molecule is nonpolar c) The molecule has identical bond angles of 120 o. d) There are several resonance structures for this molecule. e) The molecule is polar 1

2 5. Balance the following equation. What is the sum of the coefficients of the reactants and products? 2 Ag 2 CO 3 (s) 4 Ag(s) + _1 O 2 (g) + 2 CO 2 (g) a) 7 b) 8 c) 9 d) 10 e) Which of the following equations represents an acid-base neutralization reaction? a) H 2 SO 4 + Zn ZnSO 4 + H 2 b) Ba(OH) 2 + Na 2 SO 4 BaSO 4 + 2NaOH c) HCl + AgNO 3 HNO 3 + AgCl d) HNO 3 + KOH KNO 3 + H 2 O acid + base salt + water e) WO H 2 W + 3 H 2 O 7. What is the oxidation number for chlorine in HClO 3? +1 + Cl + 3(-2) = 0 Cl = +5 a) -1 b) -7 c) +1 d) +5 e) Identify the oxidizing agent in the following oxidation-reduction reaction NiO + Al Al 2 O Ni Ni 2+ accepts electrons from Al a) Ni 2+ b) O 2- c) Al d) Al 3+ e) Ni 9. A hospital patient is given a solution containing 9.00 x 10-9 g of iodine-131 (isotopic weight: 131). How many atoms of iodine are present? Avogadro s Number = 6.02 x a) 4.14 x b) 6.68 x x 10-9 g x 1 mol x 6.02x10 23 atoms c) 1.36 x g 1 mol d) 1.36 x 10 9 e) 4.14 x In which of the following pairings of masses does the first listed mass contain more moles of substance than the second listed mass? a) g H 2 O and g NH 3 b) g CO 2 and g CO calculate molar masses, then moles of each c) 105 g CH 4 and 105 g NO 2 d) more than one correct response e) no correct response 2

3 11. In the following reaction, how many grams of H 2 O are produced if 6.13 g of N 2 H 4 react? N 2 H 4 + 3O 2 2NO 2 + 2H 2 O M.W a) 1.72 g M.W. = b) 3.45 g c) 12.3 g d) 6.89 g 6.13 g x 1 mol x 2 mol H 2 O x g e) 8.96 g g 1 mol N 2 H 4 1 mol 12. How many moles of carbon monoxide will be produced from the reaction of 1.5 moles of SiO 2 and 1.5 moles of carbon? (Hint: one reagent is limiting) SiO C SiC + 2 CO a) moles 1.5 moles b) c) 1.5 limiting reagent has lowest mole to coefficient ratio d) 2.0 e) moles C x 2 CO 3 C 13. How many moles of oxygen atoms are in g of Al 2 (SO 4 ) 3? F.W. Al 2 (SO 4 ) 3 = amu a) g x 1 mol x 12 moles O b) g 1 mol Al 2 (SO 4 ) 3 c) d) e) The mineral zircon contains 49.8% Zr, 15.3% Si and 34.9% O. What is the empirical formula? (Atomic weights: Zr = 91.2, Si = 28.1, O = 16.00) a) ZrSiO g Zr = 0.55 mol 0.55/0.54 = 1 b) ZrSiO g Si = 0.54 mol 0.54/0.54 = 1 c) Zr 2 SiO g O = 2.18 mol 2.18/0.54 = 4 d) ZrSi 2 O 4 e) ZrSiO In which of the following groupings are the three terms closely related? a) kinetic energy, energy of motion, cohesive forces b) potential energy, energy of attraction, disruptive forces c) kinetic energy, electrostatic interactions, disruptive forces d) kinetic energy, energy of attraction, cohesive forces e) potential energy, electrostatic interactions, cohesive forces Each answer (c and e) received full credit. 3

4 16. Which of the following statements concerning evaporation is INCORRECT? a) Increasing the temperature of the liquid increases the rate of evaporation. b) Evaporation causes the liquid temperature to decrease. c) Increasing the surface area of the liquid decreases the rate of evaporation. d) Molecules with energies considerably above average are those that escape from the liquid. e) Evaporation is an endothermic process. 17. Which conversion of units for pressure is CORRECT? 760 mm Hg/torr = 1 atm a) 1.14 x 10 3 mm Hg = 1.50 atm b) 228 mm Hg = atm c) 152 torr = atm d) atm = 45.6 cm Hg e) 530 torr = 530 cm Hg 18. Which of the following is NOT an indicator of STRONG intermolecular forces in liquids? a) High Vapor Pressure Low Vapor Pressure is an indication of Strong forces. b) High Heat of Vaporization c) High Viscosity d) High Surface Tension e) None of the above. 19. The pressure on a 14.4 L sample of oxygen at 748 mm Hg is increased to 1.31 x 10 3 mm Hg at constant temperature. What will be the new volume in L? a) 25.2 VP = VP b) 17.5 c) L x 748 mm Hg = V x 1.31 x 10 3 mm Hg d) 8.22 e) Gas evolved in the fermentation of sugar in wine making occupies a volume of 0.75 L at 20 o C at 720 mm Hg. What volume (L) would the gas occupy at 39 o C and 1.00 atm? a) 0.80 VP/T = VP/T b) 0.73 c) L x 720 mm Hg = V x 760 mm Hg d) 0.67 ( ) K ( ) K e)

5 21. What is the density of neon in g/l at STP? Ne = amu = 1 mol 1 mol = 22.4 L at STP a) 0.90 b) 0.45 density = mass/volume c) 1.8 = g/22.4 L d) 11.2 e) In which of the following molecules will hydrogen-bonding be the strongest? a) CH 4 no H-bonding b) NH 3 weaker H-bonding, a gas at RT c) H 2 Se no H-bonding d) H 2 no H-bonding e) CH 3 CH 2 OH stronger H-bonding to O than to N 23. Assume g of dry ice (solid CO 2 ) is placed in an evacuated 50.0 L closed tank. What will be the pressure in the tank in atmospheres at a temperature of 45 o C? Assume that all the CO 2 has been converted into gas. M.W. CO 2 = 44.01; the universal gas constant is L atm mole -1 K -1 n = g x 1 mol/44.01 g = mol a) 7.25 b) 6.10 P x V = nrt c) 10.8 P x 50 L = mol x L atm mole -1 K -1 x ( )K d) 5.38 e) Which of the following is NOT a characteristic of a solution? a) It is a homogeneous mixture. b) It is composed of one solvent plus one or more solutes. c) Solvent and solute can be separated by filtration. d) One visible phase. e) Composition can vary. 25. Which of the following statements is NOT correct? a) Most solids become more soluble in water with increasing temperature. b) The solubility of a gas in water decreases with increasing temperature. c) The solubility of a gas in water increases with increasing pressure. d) A concentrated solution contains the maximum amount of solute that can be dissolved under a given set of conditions. (correct: A concentrated solution contains a large amount of solute relative to the amount that could dissolve. The maximum amount is contained in a saturated solution.) e) When salts dissolve in water, disorder/entropy increases. 5

6 26. When an aqueous solution of potassium sulfate is mixed with an aqueous solution of barium chloride a precipitate is formed. Consult the solubility rules below and identify the spectator ions for this reaction? BaSO 4 (s) is insoluble, precipitation drives the reaction. a) K + and Cl - K + and Cl - are soluble and do not react = spectator ions b) Ba 2+ and Cl - c) K + and SO 4 2- d) Ba 2+ and SO 4 2- e) none are spectator ions 27. Which of the following binary molecules is named INCORRECTLY? a) H 2 O 2 hydrogenperoxide b) S 2 Cl 2 disulfur dichloride c) CCl 4 carbon tetrachloride d) C 2 H 6 ethane e) P 4 O 10 phosphorus decoxide (tetraphosphorus decoxide) 28. Which of the following setups is correct to calculate the number of grams of CO required to produce 3.2 moles of iron according to the following equation? (Atomic weights: Fe = 55.85, C = 12.01, O = 16.00) Fe 2 O CO 2 Fe + 3 CO 2 a) 3.2 moles Fe x 2 moles Fe x 28 g CO 3 moles CO 1 mole CO b) 3.2 moles Fe x 3 moles CO x 28 g CO 2 moles Fe 1 mole CO c) 3.2 moles Fe x 3 moles CO x 1 mole CO 2 moles Fe 28 g CO d) 3.2 moles Fe x 2 moles Fe x 1 mole CO 3 moles CO 28 g CO 6

7 29. To three significant figures, what is the percent of sulfate ions, SO 4 2-, in Al 2 (SO 4 ) 3? (Atomic weights: Al = 26.98, O = 16.00, S = 32.07) F.W. Al 2 (SO 4 ) 3 = amu F.W. SO 4 2- = amu a) 28.1 b) x amu x 100 c) amu d) 65.7 e) To avoid nitrogen narcosis and oxygen toxicity, special gas mixtures are breathed by researchers and navy personnel at great depths in the ocean. For example, a 2 % oxygen and 98 % helium mixture may be selected for work at 300 ft, where the total pressure is 10 atm. What is the partial pressure of oxygen at this depth? a) 8 atm b) 2 atm c) 0.2 atm = 10 atm x 0.02 O 2 d) 0.8 atm e) 9.8 atm 7