REAGENTS Metallic copper, Concentrated nitric acid, NaOH concentration 6M (25%), Sulfuric acid concentration 3M, Zn shot, 0.1M potassium hydroxide PROCEDURE 1 Weigh out the metallic Cu and place it in a 250mL Erlenmeyer flask. Place the flask near the window and slowly and carefully add concentrated nitric acid. After adding the acid and when the gas begins to evolve, cover the flask with the gas trap stopper and allow the gas to drain into the KOH solution. When the gas stops coming out, and if all the copper is still not dissolved, add more nitric acid and repeat the operations until the Cu dissolves completely. NO2 is released, which is a very toxic reddish-brown gas, so it is important to "catch" it. PROCEDURE 2 Accurately measure the volume of the solution obtained in the flask in the previous reaction. Take a 10 mL aliquot and place it in a 250 mL beaker. Add approximately 30 mL of water and 5 mL of 6M NaOH. Allow the precipitate to settle and if the solution is not completely discolored, add a little more NaOH until discoloration is complete. PROCEDURE 3 Heat the sample until all of the precipitate turns to cupric oxide, which is black in color. Write and balance the equation for the reaction to obtain CuO.
REAGENTS
Metallic copper, Concentrated nitric acid, NaOH concentration 6M (25%), Sulfuric acid concentration 3M, Zn shot, 0.1M potassium hydroxide
PROCEDURE 1
Weigh out the metallic Cu and place it in a 250mL Erlenmeyer flask. Place the flask near the window and slowly and carefully add concentrated nitric acid. After adding the acid and when the gas begins to evolve, cover the flask with the gas trap stopper and allow the gas to drain into the KOH solution. When the gas stops coming out, and if all the copper is still not dissolved, add more nitric acid and repeat the operations until the Cu dissolves completely. NO2 is released, which is a very toxic reddish-brown gas, so it is important to "catch" it.
PROCEDURE 2
Accurately measure the volume of the solution obtained in the flask in the previous reaction. Take a 10 mL aliquot and place it in a 250 mL beaker. Add approximately 30 mL of water and 5 mL of 6M NaOH. Allow the precipitate to settle and if the solution is not completely discolored, add a little more NaOH until discoloration is complete.
PROCEDURE 3
Heat the sample until all of the precipitate turns to cupric oxide, which is black in color.
Write and balance the equation for the reaction to obtain CuO.
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