How to Convert a Copper Metal to Aqueous Copper Ions
Chemists have known for a long time that strong acids are capable of dissolving certain metals. Copper metal can be dissolved in this manner, by adding it to concentrated nitric acid. In this reaction, each copper atom loses two electrons and so becomes a charged chemical species, or an ion. The nitric acid is also changed as it reacts with the metal, turning into a mixture of water and nitrogen dioxide gas. The end result of the reaction is that the copper metal turns into copper ions in a water solution.
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Things You'll Need
- Copper metal
- Scale
- Beaker
- Concentrated nitric acid
- Tongs
- Hot plate (optional)
Instructions
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Put on appropriate personal protective equipment; acid-resistant gloves, lab coat and goggles. Put all your glassware, chemicals and apparatus in a chemical fume hood.
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2
Cut off a portion of copper from a spool of wire or some other source of this metal. Weigh the portion you have taken.
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3
Pour some concentrated nitric acid (HNO3) from its bulk container into a labeled beaker. Use about 5 mL of acid for every 0.5 g of copper metal you have in your sample.Perform this step, and all others in the fume hood.
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4
Place your portion of copper metal in the beaker with the acid. Lower the metal slowly and carefully so it does not splash the acid. You can use tweezers or tongs to make this safer.
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Allow the metal to sit in the acid. It will react with the nitric acid to produce copper ions with a double positive charge, known as Cu(II). The reaction will also make nitrogen dioxide, which will escape from the beaker as a brownish gas. The equation for this reaction is Cu(s) + 4H+(aq) + 2NO3-(aq ) --> Cu2+(aq ) + 2NO2(g ) + 2H2O(l).
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Tips & Warnings
You can heat the nitric acid (keep its temperature below boiling) to speed up the reaction of the acid with the copper.
Read the Material Safety Data Sheet (MSDS) for nitric acid before you begin.
Concentrated nitric acid is very dangerous. It is corrosive by skin contact, and its vapors are also harmful. Do not allow any acid to contact your skin. Work in a fume hood so you don't breathe in any fumes.
The fumes produced by the reaction of copper and nitric acid are very dangerous. Do not breathe them in or allow them to come in contact with your bare skin.
Nitric acid is very reactive with many common materials and solvents. Dispose of the used acid in an appropriate hazardous waste container, and do not mix with other waste.
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