CHEM 140

CHEM 171 - Fall 2012Name: _________________________________Take-Home Worksheet Not to be turned in Answers on Canvas

1. You add 0.2916 grams of a Metal Hydroxide, M(OH)2, to water and then titrate using 25.84 mL of a 0.3870 M HNO3 solution. What is the Metal, M? {H+ + OH H2O}

2.You mix 400.0 mL of a 0.120 M Lead (II) Nitrate with 600.0 mL of a 0.100 M Sodium Iodide and a yellow Lead (II) Iodide precipitates. (PbI2 = 461.00 g/mol)Pb(NO3)2(aq) + 2 NaI(aq) PbI2(s) + 2 NaNO3(aq)a. How many grams of Lead (II) Iodide can theoretically form? (think limiting reactant)b. What are [Pb2+], [Na+], [I], and [NO3] after precipitation is complete (total end volume = 1000.0 mL)?

__________________ = Limiting Reactant_______________ grams PbI2

______________ M = [Pb2+]_______________M = [Na+]

________________ M = [I]________________M = [NO3]

3.Assign Oxidation Numbers for each atom in the following compounds and ions. Again, the oxidation number is per atom (e.g. H2O has a +1 for Hydrogen, not +2)

Fe2O3: Fe = __ O = __SnCl2 : Sn = __ Cl = __C2H6: C = __ H = __NH4+ : N = __ H = __MgO2: Mg = __ O = __Cr2O72: Cr = __ O = __