M = Molarity = mol solute L solution. PV = nrt % yield = actual yield x 100 theoretical yield. PM=dRT where d=density, M=molar mass

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1 Solubility Rules: 1. Most nitrate salts are soluble. 2. Most salts of alkali metals and ammonium cations are soluble. 3. Most chloride, bromide and iodide salts are soluble. Exceptions: salts containing Ag +, Pb 2+ and Hg 2 2+ ions are insoluble 4. Most sulfate salts are soluble. Exceptions: sulfates containing Ca 2+, Ba 2+, Pb 2+ and Hg 2 2+ ions are insoluble 5. Most hydroxide salts are insoluble. Exceptions: hydroxides containing alkali metals, Ba 2+, Sr 2+ and Ca 2+ ions are soluble 6. Most sulfide, carbonate, chromate and phosphate salts are insoluble. Exceptions: salts of alkali metals and ammonium cations are soluble Useful Constants and equations: K = o C M = Molarity = mol solute L solution PV = nrt % yield = actual yield x 100 theoretical yield R = L atm / mol K Avogadro's number = x STP = 1 atm, 273 K PM=dRT where d=density, M=molar mass 1 atm = 760 torr d = density = mass/volume mass % of A = mass of A x 100 P 1 V 1 = P 2 V 2 total mass n 1 T 1 n 2 T 2

2 1. (4) Ethanol, C 2 H 6 0 is being added to gasoline to provide a renewable fuel for cars. It burns as shown below in an unbalanced reaction: C 2 H 6 O (l) + O 2 (g) CO 2 (g) + H 2 O (l) If 150 g of ethanol is mixed with 192 g of oxygen, what mass of carbon dioxide will be produced? (Molar masses C 2 H 6 O= g/mol, O 2 = g/mol, CO 2 = g/mol, H 2 O = g/mol). a) 132 g CO 2 b) 176 g CO 2 c) 194 g CO 2 d) 264 g CO 2 e) 388 g CO 2 2. (4) A compound contains only carbon, hydrogen and oxygen. Combustion of 7.30 mg of the compound yields mg of carbon dioxide and 4.37 mg of water. What is the empirical formula of this compound? a) CHO b) C 2 HO c) CH 2 O d) CHO 2 e) none of these (a-d) 3. (4) A sample of copper sulfate pentahydrate, CuSO 4. 5H 2 O, contains g of Cu. How many grams of oxygen are in this same sample? a) g b g c) g d) g e) 8.57 g 4. (4) Automobile airbags inflate when sodium azide, NaN 3, decomposes explosively to form the elements, Na (s) and N 2 (g). How many grams of NaN 3 are needed to produce 5.00 g of nitrogen gas? (Molar masses, NaN 3 = g/mol, Na = 22.99, N 2 = g/mol) a) 23.2 g b) 17.4 g c) 11.6 g d) 8.58 g e) 7.73 g 5. (4) The analysis of a gaseous compound revealed that it was 85.7% C and 14.3% H by mass. When 1.77 g of the gas is stored in a L flask at 17 o C it has a pressure of 1.10 atm. What is the molecular formula of the compound? a) CH 2 b) CH 4 c) C 2 H 2 d) C 2 H 4 e) C 2 H 6

3 6. (4) An unknown diatomic gas has a density of g/l at STP. What is the identity of the gas? a) N 2 O 4 b) SO 2 c) Kr d) Cl 2 e) Br 2 7. (4) Consider the following reaction: 2 N 2 O 5 (g) 4 NO 2 (g) + O 2 (g) mol of N 2 O 5 is initially placed in a 5.00 L container at 27 o C. What is the total pressure in the 5.00 L container after all of the N 2 O 5 decomposes to form the products, all at 27 o C? a) 6.15 atm b) 4.10 atm c) 3.08 atm d) 2.05 atm E) 1.03 atm 8. (3) Which of the following statements regarding samples of F 2 (g) and Cl 2 (g) in identical containers at STP are true? I. They contain the same number of molecules II. The F 2 sample has a smaller average kinetic energy III. If a pinhole leak occurs in each container, the F 2 gas will escape faster IV. The F 2 sample will obey the ideal gas law more closely a) II and III b) II and IV c) I, II and IV d) I, III and IV e) I, II, III and IV 9. (4) A sample of propane, C 3 H 8, of unknown mass, is contained in a vessel of unknown volume at 35.5 o C and a pressure of 1.05 atm. To this vessel 5.67 g of Ar are added so that no propane is lost from the vessel. The final pressure of the vessel is 1.87 atm at the same temperature. Calculate the mass of the propane sample. a) 0.89 g b) 8.01 g c) 16.1 g d) 41.3 g e) 82.5 g 10. (4) The rate of effusion of chlorine gas is 1.5 times faster than the rate of effusion of an unknown gas, with both gases at 350 K. What is the unknown gas? a) fluorine b) hydrogen c) bromine d) oxygen e) krypton

4 11. (4) A new gaseous element is discovered leaking from a fissure in the ocean floor. The new element, Illinium, is collected in a 10 L cylinder at a pressure of 1777 torr and temperature of 12 C. When it is brought to the surface, still in the 10 L tank, the temperature is 30 C. If the mole fraction of water in gas sample is 0.23, and the dry Illinium gas weighs g, what is the molar mass of Illinium? a) 329.9g/mol b) g/mol c) g/mol d) g/mol e) g/mol 12. (3) For which of the following substances will LDF be the only significant factor in determining its boiling point? I. Cl 2 II. HF III. Ne IV. KNO 2 V. CCl 4 a) I, III and V b) I, II and III c) II and IV d) II and V e) III, IV and V 13. (3) Which of the following gases would be the most soluble in water? a) CO 2 b) Br 2 c) Cl 2 d) O 2 e) NH (4) A solution is made by mixing 50.0 ml of 6.00 M HCl with ml of M HCl. This mixture is diluted by adding water until the final volume in ml. What is the molarity of the final solution of HCl? a) M b) M c) M d) M e) 1.00 M Use the following information to answer the next two (2) questions. When 50.0 ml of a 1.00 M aqueous solution of Fe(NO 3 ) 3 is mixed with 50.0 ml of a 1.00 M aqueous solution of NaOH, a precipitate forms. 15. (4) What ions remain in solution after the reaction is completed? a) Fe 3+ and OH - b) Fe 3+, Na + and NO 3 - c) Fe 3+, OH -, Na + and NO 3 - d) Na + and NO 3 - e) Na +, NO 3 -, OH -

5 16. (4) Determine the mass of the solid produced in this reaction. a) 0.35 g b) 1.78 g c) 2.67 g d) 5.34 g e) 7.96 g 17. (4) Which of the following is the net ionic equation when 0.10 M solutions of magnesium chloride and potassium sulfate are mixed together? a) MgCl 2 (aq) + K 2 SO 4 (aq) MgSO 4 (s) + 2 KCl (aq) b) MgCl 2 (aq) + K 2 SO 4 (aq) 2 KCl (s) + CaSO 4 (aq) c) Mg 2+ (aq) + SO 4 2- (aq) MgSO 4 (s) d) 2 K + (aq) + 2 Cl - (aq) 2 KCl (s) e) No reaction takes place 18. (4) Coenzyme A contains one sulfur atom per molecule. When it is decomposed the sulfur is converted to sulfide. A 56.0 g sample of coenzyme A is decomposed and the sulfide released is completely precipitated by its reaction with 73 ml of 2.00 M AgNO 3. What is the molar mass of coenzyme A? a) 192 g/mol b) 384 g/mol c) 576 g/mol d) 767 g/mol e) 1534 g/mol 19 The heat of vaporization, H vap or a substance is related to the strength of its intermolecular forces. Arrange the following species in order of decreasing molar H vap. CH 3 NH 2 NH 4 NO 3 CH 4 CCl 4 CH 3 F a) CH 3 NH 2 > NH 4 NO 3 > CH 4 > CCl 4 > CH 3 F b) NH 4 NO 3 > CH 3 NH 2 > CCl 4 > CH 3 F > CH 4 c) CH 4 > CCl 4 > CH 3 F > CH 3 NH 2 > NH 4 NO 3 d) CH 3 F > CH 3 NH 2 > NH 4 NO 3 > CH 4 > CCl 4 e) CH 3 NH 2 > NH 4 NO 3 > CH 3 F > CCl 4 > CH 4 20 Which of these compounds will form hydrogen bonds with each other? a) NH 4 NO 3 and CH 4 b) CH 3 NH 2 and CH 3 F c) CH 3 F and CCl 4 d) none of these combinations (a-c) will form hydrogen bonds e) all of these combinations (a-c) will form hydrogen bonds

6 21. (4) Consider the following reaction: 2 N 2 O 5 (g) 4 NO 2 (g) + O 2 (g) mol of N 2 O 5 is initially placed in a 5.00 L container at 27 o C. What is the total pressure in the 5.00 L container after all of the N 2 O 5 decomposes to form the products, all at 27 o C? a) 6.15 atm b) 4.10 atm c) 3.08 atm d) 2.05 atm E) 1.03 atm

CHEMISTRY 102A Spring 2012 Hour Exam II. 1. My answers for this Chemistry 102 exam should be graded with the answer sheet associated with:

CHEMISTRY 102A Spring 2012 Hour Exam II. 1. My answers for this Chemistry 102 exam should be graded with the answer sheet associated with: . My answers for this Chemistry 0 exam should be graded with the answer sheet associated with: a) Form A b) Form B c) Form C d) Form D e) Form E. A sample of LSD (D-lysergic acid diethylamide, C 4 H 30