Percentage yield of copper

Copper reacts with many other elements in nature to form many different copper ores. Mining companies must first locate and then analyse deposits of copper ores to determine if it is commercially feasible to extract the copper. The percentage of copper by mass that is present in a sample of ore is determined by chemists. In this experiment we will see how we can extract copper from a sample of copper ore. The techniques that will be used here are not always possible on a commercial scale.

Teachers should perform this activity first to identify any other possible hazards that have not been listed here.

Equipment:
- prepared ore pellets;
- two pieces of filter paper;
- funnel;
- two 100 mL beakers;
- mortar and pestle;
- 2.0M sulfuric acid solution;
- latex gloves, goggles, overcoat;
- distilled water;
- zinc metal.

Make sure the pellets of ore are completely dry.

 
Crush one of the ore pellets with a mortar and pestle.

Weigh a 100 mL glass beaker.

Transfer the crushed ore into the beaker and weigh the beaker and its contents.

Calculate the mass of ore present in the beaker.
Into the beaker containing the ore pour 40 mL of 2.0 M sulfuric acid. Always wear gloves as sulfuric acid is very corrosive.
You will see the solution start to fizz. Carbon dioxide is produced as the acid reacts with the carbonate in the ore. The insoluble carbonate will eventually be dissolved. Leave the mixture overnight, in a fume cupboard, for the reaction to complete.

A blue solution will form when all the copper carbonate has dissolved. The blue colour is due to the copper present in the solution. Insoluble rock will be present at the base of the beaker.

We must now separate the copper in the solution from the rock at the bottom of the beaker using filtration.

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