Chem 121 Second Exam February 11, 2005 Name______________________Chem 121 Second Exam February 11, 2005 Name______________________Show all your work! No calculations, no points!1. (10 points) How much oxalic acid (C2O4H2) will you need to make 100.0 mL of a 0.75 M solution?6.7 g2. (5 points) Using the 0.75 M solution prepared in the question above, describe how you could make 40.0 mL of a 0.035 M oxalic acid solution?1.8 mL 0.75 M Oxalic acid + 38.2 mL water3. (25 points) Aluminum and hydrogen ion react as follows:2 Al(s) + 6 H+(aq) ---- 2 Al+3(aq) + 3 H2(g)How many grams of hydrogen gas are evolved when 4.00 g Al react with 500 mL of 4.00 M HCl?0.44 g hydrogenWhat is the [H+] after the reaction is over?3.12 M4. (20 points) Determine the number of grams of S present in each of the following:a. 10.0 g H2SO43.26 gb. 1.37 moles CS287.7 gc. 3.00 x 1020 molecules S4N40.0638 g5. (20 points) Write net ionic equations for the reactions that occur when the followingaqueous solutions are mixed: [N.B. all phosphates are insoluble except for theusual suspects. all chlorides are soluble except Ag, Hg and Pb..]a. Ammonium chloride and sodium acetateNH4+(aq) + C2H3O2-(aq) NH3(aq) + HC2H3O2(aq)b. Calcium chloride and potassium phosphate3 Ca+2(aq) + 2 PO4-3(aq) Ca3(PO4)2 (s)6. (20 points) A hydrocarbon CxHy when burned completely yields CO2 and H2O in a mass ratio of 1.995 to 1. Calculate the empirical formula of the
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