1. Quiz (2): Second year student, Chemistry-Physics group
  2.  
  3. A mass of 1.225 g of sodium oxalate (MW = 134.00 mg/mol) is placed in a 100.0 mL volumetric flask. A 10.00 mL aliquot is placed in 100 mL of water and titrated with 32.99 mL of potassium permanganate.
    1. Show the reaction equation between potassium permanganate and sodium oxalate.

(4)

    1. What is MKMnO4?

(8)

  1. Write balanced net ionic equations for the following reactions. Identify the oxidation and reduction for each reaction.
    1. Cl- + MnO2(s) ==== Cl2(g) + Mn2+

(6)

    1. IO3- + I- === I2(aq)

(6)

    1. IO3- + I- + Cl- === ICl2-

(6)

    1. I2 + H2S === I- + S(s)

(6)

  1. A solution contains 9.00% (w/w) NaOH (MW = 40.0 g) and has a density of 1.098g/mL. 20 mL of this solution is diluted to 500 mL.
  2. a) Calculate the pH of the final, diluted solution. (pH = ............... )

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b) BONUS: Calculate the pH of the original solution before it was diluted.  Assume complete dissociation.  Be careful.  Think!!  ( pH = .............)

3

  1. Calculate the molar concentration of H3O+in the final solution prepared by dissolving 5.36 g of benzoic acid C6H5COOH --- (MW = 122.1 g/mol)--- in 100 mL of water and diluting 20 mL of this solution to 500 mL, and finally diluting 50 mL of this to 250 mL.  (H3O+ =  ................ M)

7

  1. What weight of sodium acetate (MW = 82.03 g/mol) must be added to 600 mL of 0.800 M acetic acid to produce a buffer with a pH of 5.00? ( ..................... g)

8

  1. A 12.5% (w/w) NiCl2 (MW=129.61 g/mole) solution has a density of 1.149 g/mL. Calculate.
  2. The molar concentration of NiCl2 in this solution,

8

  1. The mass in grams of NiCl2 contained in each liter of this solution

2

  1. Ten milliliters of a 0.1123 M solution of HCl is diluted in a 100.0 mL volumetric flask. A solution containing sodium hydroxide (MW=40.00 g/mol) requires 5.76 mL of the dilute HCl for neutralization. How many milligrams of NaOH are in the sodium hydroxide solution?

5

  1. What Na2CO3 mass (MW=105.9 g/mole) is required to neutralize 22.31 mL of 0.1017 M HCl.

5

  1. 2.5543 grams of Na2CO3 (MW=105.9 g/mole) are placed in a 500.0 mL volumetric flask. A 25.00 mL aliquot of this solution is neutralized with 17.55 mL of HCl. What is the molarity of the HCl solution