c127e3p3f2000

1. Consider the following reaction: 2AgNO₃(s) + BaC₂(s) 2AgC(s) + Ba(NO₃)₂(s) The heats of formation ( H_f^o) are as follows:
   AgNO₃(s) -124.4 kJ/mol
   BaC₂(s) - 858.6 kJ/mol
   AgC(s) -127.1 kJ/mol
   Ba(NO₃)₂(s) - 992.0 kJ/mol
   1. What is the enthalpy ( H^o) for the reaction?

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      + - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

   2. Is the reaction exothermic?

      yes no

   3. At standard conditions, what is H when 56 g of AgNO₃ (MM = 169.9 g/mol) reacts?

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      + - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

   4. If the heat involved (above) is transferred without loss to 100.0 g of water at 25^oC, what is the final temperature of the water (c_water = 4.18 J/g-^oC)?

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      + - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

2. 1. An aqueous solution of potassium permanganate is

      colorless blue purple orange green light yellow

   2. Bromine in hexane is

      colorless blue purple orange green light yellow

   3. Iodide ion in aqueous solution is

      colorless blue purple orange green light yellow

   4. When a colorless solution containing Fe²⁺ is titrated with KMnO₄, the appearance of a

      colorless blue purple orange green light yellow solution indicates that phosphoric acid must be added.

3. Consider the following substances: A(NO₃)₂, B(NO₃)₂, and C(NO₃)₂. Given below is their solubility with respect to 3 aqueous solutions:
   A(NO₃)₂ soluble in H₂SO₄ and KIO₃; insoluble in Na₂CO₃
   B(NO₃)₂: soluble in KIO₃; insoluble in H₂SO₄ and Na₂CO₃
   C(NO₃)₂: soluble in H₂SO₄ and Na₂CO₃; insoluble in KIO₃
   The identity of a white solid is determined by testing its solubility in each of the solvents. When a sample of the white solid is added to a solution of KIO₃, the solid dissolves. Another sample added to Na₂CO₃ did not dissolve. A third sample of the white solid added to H₂SO₄ dissolved. What is the cation present in the white solid?

   A cation B cation C cation

4. A student weighs an empty flask with its stopper and finds the mass to be 60.5002 g. He then adds 20.00 mL of CC₄ (MM = 153.8 g/mol) to the flask and heats the flask in a water bath until the last drop of unknown liquid has vaporized. He immediately stoppers the flask while removing it from the water bath and allows it to cool on the bench top. When the flask has cooled to room temperature, the student removes the stopper momentarily, replaces it, and weighs the flask, stopper and condensed vapor obtaining a mass of 61.5126 g. The volume of the stoppered flask is 200.0 mL and the barometric pressure in the laboratory is 752 mm Hg.
   1. What is the vapor pressure in the flask (in atm) after the student removes the stopper momentarily and then replaces it?

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      + - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

   2. How many moles of condensed CC₄ vapor are present?

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      ± w.xy E{± ab}, and then press the Submit button (below).

      + - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

   3. What is the temperature (in K) of the vapor of the unknown liquid when it fills the volume of the flask?

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      ± w.xy E{± ab}, and then press the Submit button (below).

      + - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

What's your answer? Choose your answer in scientific notation, i.e.,

+ - 1 2 3 4 5 6 7 8 9 . 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 E{ + - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 }

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Query, are the (above) answers correct?