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Unformatted text preview: Exam 2 answer key for Tuesday 7 October 08 The test version is listed before problem 1, after problem 28, and before problem 32. Students were given four points for writing their name on all the partial credit pages and writing the name & version on the brown scantron. PART I : Each question is worth 2.25 pts for a maximum of 63 pts. tau is , upsilon is # - 2-T - 2-U - 2-T - 2-U Topic % correct 1 e ab electrolytes 2 ae d c a oxidation state 3 e ab a c activity series 4 a b b d identifying oxidation or reduction 5 ac ab d d naming displacement/redox 6 ab ab e a noble metals 7 ac ae spectator ions 8 a c ae e driving forces 9 b a d ab driving forces 10 e b ab b driving forces 11 c d b e driving forces 12 d e ab d driving forces 13 d e ab ab solubility 14 e e d e concentration of ions 15 b e e d mass of solute 16 b e e b moles from mass 17 a d e d molarity from mass and volume 18 b e e a dilution 19 ab c c d finding molarity not a dilution problem 20 ab ab ab c titration but not 1:1 stoichiometry 21 b c d ab enthalpy 22 b d b d internal energy, heat and work 23 ac ac b d enthalpy change from reactant amount 24 b c product amount from enthalpy change 25 d b ac ab heat capacity of water 26 ad b c c heat capacity of a bomb calorimeter 27 d d d a Hess law 28 c e enthalpy change from enthalpy of formations If you think you spot an error, please let Dr. Eng know. He can be reached at his email address: email@example.com. Exam 2 answer key for Tuesday 7 October 08 The test version is listed before problem 1, after problem 28, and before problem 32. PART II maximum is 33 pts. Different versions had different numbers. The net ionic equation problems (8 pts) For the reactants below, if there is a reaction, (1) write the balanced molecular equation, write the complete ionic equation, and write the net ionic equation from the balanced molecular equation. If there is no reaction, write NR. Assume the reactants are aqueous, unless they are insoluble in water. Each version had # potassium acetate and chromium (III) bromide One might expect 3 KC 2 H 3 O 2 (aq) + CrBr 3 (aq) 3 KBr (aq) + Cr(C 2 H 3 O 2 ) 3 (aq) but because each reactant and product is aqueous and ionic, only spectator ions will be present in the complete ionic equation; thus, there is no reaction. balanced molecular equation NR 4 pts (1.5 pts partial for above balanced reaction) complete ionic equation net ionic equation -2-T b. strontium nitrate and ammonium sulfide balanced molecular equation Sr(NO 3 ) 2 (aq) + (NH 4 ) 2 S (aq) SrS (aq) + 2 NH 4 NO 3 (aq) complete ionic equation...
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This note was uploaded on 07/10/2011 for the course CHM 2045 taught by Professor Eng during the Fall '10 term at UNF.
- Fall '10