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CHEM1211K Homework Chapter 4 Spring 2013

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Show your math for full credit.

1.  Write the net ionic equation for the precipitation reaction that occurs when aqueous solutions of silver nitrate and potassium phosphate are mixed.

2.  What is the oxidation state of the indicated element in each of the following substances:

a.  S in SO2

b.  C in COCl2

c.  S in H2SO3

d.  Mn in KMNO4

e.  Cl in HClO2

3.  Which element is oxidized and which is reduced in the following reactions:

a.  N2 (g) + 3 H2 (g) → 2 NH3 (g)

b.  Cl2 (aq) + 2 NaI (aq) → I2 (aq) + 2 NaCl (aq)

4.  Calculate the number of moles of bromide ions in 0.900 L of a 0.500M solution of AlBr3.

5.  Calculate the concentration (M) of sodium ions in a solution made by diluting 40.0 mL of a 0.474 M solution of sodium sulfide to a total volume of 300 mL.

6.  Pure acetic acid (HC2H3O2) is a liquid and is known as glacial acetic acid. Calculate the molarity of a solution prepared by dissolving 10.00 mL of glacial acetic acid at 25 °C in sufficient water to give 500.0 mL of solution. The density of glacial acetic acid at 25 °C is 1.05 g/mL.

7.  A 31.5 mL aliquot of H2SO4 (aq) of unknown concentration was titrated with 0.0134 M NaOH (aq). It took 23.9 mL of the base to reach the endpoint of the titration. Calculate the concentration (M) of the acid solution.

8.  What are the respective concentrations (M) of Na+ and SO42- afforded by dissolving 0.500 mol Na2SO4 in water and diluting to 1.33 L?

9.  Calculate the number of grams of solute in 500.0 mL of 0.189 M KOH.

10.  Lead ions can be precipitated from aqueous solutions by the addition of aqueous iodide:

Pb2+ (aq) + 2I- (aq) → PbI2 (s)

Lead iodide is virtually insoluble in water so that the reaction appears to go to completion. How many milliliters of 3.550 M HI(aq) must be added to a solution containing 0.700 mol of Pb(NO)3)2 (aq) to completely precipitate the lead?