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Unformatted text preview: 1 Chemistry 125/126 Spring 2008 Exam 1 Name: ___________________________________ R = 0.0821 L.atm/mol.K R = 8.314 J/mol.K N A = 6.022 x 10 23 mol-1 o 2 / 1 o 2 / 1 o o 2 / 1 o ] A [ k 1 t kt ] A [ 1 ] A [ 1 k 2 ln t kt ] A [ ] A [ ln k 2 ] A [ t kt ] A [ ] A [ = =- =- = =- =- 1 a E RT a k Ae E ln k ln A R T- = =- =- =- =- q = s . m . T Specific Heat of Water = 4.18 J/ o C.g S g = k P g P A = X A P A T b- T b = T b = i K b m T f- T f = T f = i K f m = i MRT For water: K b = 0.51C/m; K f = 1.86C/m 1 2 2 1 1 1 a E k ln k R T T =- =- =- =- - =- 1 2 1 1 2 1 T T R H ) P ln( ) P ln( vap T , vap T , vap Molarity = moles of solute/Liters of solution Molality = moles of solute/Kg of solvent 2 Multiple Choice Section (3 points each): 1) Ammonium cyanate (NH 4 CNO) reacts to form urea (NH 2 CONH 2 ). At 65 C the rate constant, k , is 3.60 L mol-1 s-1 . What is the rate law for this reaction? A) Rate = 3.60 L mol-1 s-1 [NH 4 CNO] B) Rate = 3.60 L mol-1 s-1 [NH 4 CNO] 2 C) Rate = 0.28 mol L-1 s [NH 4 CNO] D) Rate = 0.28 mol L-1 s [NH 4 CNO] 2 E) more information is needed to determine the order. 2) In hydrogen iodide _____________ are the most important intermolecular forces. A. dipole-dipole forces B. London dispersion forces C. hydrogen bonding D. covalent bonds. E. polar covalent bonds. 3) Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H + + H 2 O 2 H 2 O + OH (rapid equilibrium) H 2 O + OH + Br- HOBr + H 2 O (slow) HOBr + H + + Br- Br 2 + H 2 O (fast) Which of the following rate laws is consistent with the mechanism?...
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