Spring 2006 Exams

# Spring 2006 Exams - CHM 2045 Exam 1(Fonn Code A January...

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CHM 2045 Exam 1 (Fonn Code A) January 31,2006 Instructions: On your scantron sheet enter your name, UF ID number [in place of SSNJ (start on the first space and leave the last space blank), Discussion Section No. and Form Code (see above). This exam consists of 20 multiple choice questions each worth 12.5 points for a total maximum of 250 pts. You may retain your exam sheet (mark your answers on it and the scantron sheet). Turn in only the scantron. You may not use anything but your own calculator and writing instruments during this exam, sharing is not allowed. Please work alone. Your name on this exam states the assertion: "I herebypledge that I have neither given nor received unauthorized aid during this exam. " If you line up 2.62 x 1dZ sodium atoms side by side, what is the length of the line of Na atoms in miles? Assume the atoms are spheres of radius 0.186 nm. (1 mile = 1.609 km.) (1) 3.04 x 10" mi (2) 4.87 x 10" mi (3) 6.09 x 10" mi (4) 6.06 x 1 o9 mi (97.1 x 10"mi How many moles of oxygen are required to combust one mole of dimethyl ether, (H3C)z0, and produce C02 and water as sole products? (1) 3.0 mols (2) 2.5 mols (3) 3.5 mols (4) 4.0 mols (5) 5.0 mols Given the thermochemical information: AH"Mion (H20 oh) ) = -285.8 Wmol AHOrmh (C2H2 (,)) = -26.7 kJ/mol AHO,,,,.,,,,, (Cq 0 ) = -393.5 kJ/mol The molar heat of combustion of acetylene, C2H2 (,,, is closest to? (1) -26.7 kJIm01 (2) -695.2 W/mol (3) -706.00 Wmol (4) -1 046.1 kJ/mol (5) -1072.3 kJ/mol If an aqueous NaOH solution is 14.6% by mass NaOH and has a density of 1.10 g/mL, the molarity, M, of this solution is closest to (1) 5.00 A4 (2) 4.00 M (3) 5.50 M (4) 3.50 M (5) 3.00 M Which one of the following ions has the same number of electrons and neutrons? (1) 48 ~i~+ (2) 35 CI- (3) 3- (4) 40 ~r 2+ (5) 80 Br - If a 10.0 g Cu block is heated to100.0 "C and then plunged into 100.0 g of water at 25.0 OC, which of the following statements best characterizes the final temperature (Tf)? [The specific heat capacity of Cu(s) is 0.386 J/g°C] (l)Tf>lOO.OOC (2)TfG5.00C (3)Tf-d2.50C (4) Tf=37.5 OC (5) Tf will be slightly greater than 25.0 OC The volume contained in a cube 1.00 mm on a side is: (1) 1 .OOL (2) 1.00 mL 1 .OO pL (4) 1 .OO nL Consider the complete combustion of 1.234 g of C12H2402 (molar mass = 200.3 g/mol) in excess oxygen gas. The mass of oxygen gas required by this reaction is closest to? (1) 0.1971 g (2) 1.676 g (3) 3.253 g (4) 3.351 g (5) 6.702 g

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9. Magnesium nitride (Mg3N2) can be formed by the reaction of magnesium metal with nitrogen gas. The mass (in g) of magnesium nitride that is formed in the reaction of 35.00 g of magnesium with excess nitrogen is closest to (1) 5443 (2) 484 (3) 134 (4) 2443 (5) 101.g 10. The volume (in mL) of a 2.00 M CuS04 stock solution that is needed to prepare 0.250 L of 0.400 M CuS04 is closest 0.05 mL (2) 0.5 (3) 5.0 (4) 5O.mL (5) 500. mL
Code A 1 I. The reaction between Al and C12 produces AIC13. If 64.30 g C12 and 64.30 g Al are used, which reactant is in excess and how much of it will be left over after the reaction goes to completion? (Hint write a balanced equation.) (1) Al, 16.3 1 g (2) Al, 47.998 (3) CI2, 47.998 (4) C12, 16.3 1 g (5) Al, 3 17.8 g 12. When 24 copper pennies are submerged in water, the pennies displace 8.26 cm3 of water. If the mass of all the nnies is 73.86 g, the density of copper is closest to? 5" (1) 0.1 12 g/cm (2) 1.34 g,/crn3 (3) 8.94 g/cm3 (4) 32.8 glcrn3 (5) 107 g/cm3 13. Which of the following statements are correct? a. Atomic number equals number of protons plus neutrons.

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Spring 2006 Exams - CHM 2045 Exam 1(Fonn Code A January...

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