Physical/Chemical Properties of Copper
Use this demo to contrast the physical and chemical properties of matter. Chemical properties are based on the ability or inability of the substance to produce new substances. Copper's malleability, color, luster, and thermal and electrical conductivity are contrasted with its ability to react with concentrated nitric acid and silver nitrate.
This demo should be used at the beginning of an intro chemistry course when the concepts of physical and chemical properties are being introduced and contrasted. Allow about 15 minutes for this demo.
- Properties of a substance that can be observed without attempting to change the substance into another substance are physical properties. If the investigation of a property involves an attempt to change the substance into another substance, that property is a chemical property.
- The equation for the reaction of nitric acid with copper is: Cu(s) + 4HNO3 ==> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)
- The equation for the reaction of copper with silver nitrate solution is: Cu(s) + 2AgNO3(aq) ==>2Ag(s) + Cu(NO3)2(aq)
- a piece of copper foil about 6 cm square
- an insulated flask clamp
- light bulb conductivity apparatus
- Vernier lab interface with temperature probe
- Petri dish with a 0.5 cm x 1.0 cm piece of copper foil in it
- small bottle of 0.1 M silver nitrate solution
- 1 L Florence flask with a stopper containing a 0.5 cm square piece of copper foil
- document camera
- video projector
- Use the large piece of copper foil to demonstrate the color, luster, and malleability of copper.
- Fasten the copper foil in the clamp, turn on the power to the conductivity apparatus, and touched the copper to both electrodes of the apparatus simultaneously. The apparatus should light up. Turn off the power to the apparatus.
- Wrap the foil around the thermometer probe of the Vernier thermometer and clasp it tightly with your hand. The display will register the increase in temperature as your body heat is conducted through the copper foil into the probe. The computer monitor display can be projected in most classrooms.
- Pour enough silver nitrate solution into the Petri dish to cover the small piece of copper in it. Proceed to the nitric acid part of the demo to allow this to react for a while, then return to this reaction. After a few minutes bright silver needles will have formed on the copper. Projection is highly recommended for this part of the demonstration.
- Drop a few drops of concentrated nitric acid onto the small piece of copper in the Florence flask. Immediately replace the stopper. The nitric acid and will react with the copper to produce maroon nitrogen dioxide gas. Projection enhances this part of the demonstration.
- Make sure that the copper foil does not touch the metal part of the clamp used in the electrical conductivity demonstration. The electrodes of the conductivity apparatus are at 120 VAC. Be careful not to touch them while the power is on.
- Nitric acid is highly corrosive. Wash immediately with soap and water if any gets on your skin. In the event of a nitric acid spill, cover the nitric acid with the sodium carbonate that is provided and evacuate the room if necessary.
- Aqueous silver nitrate is a strong oxidizer. If any gets on your skin, wash it off with soap and water immediately.