Which oxide is formed when copper carbonate decomposes.

Introduction

Aim

Copper has two oxides, namely, CuO and Cu2O. Copper carbonate, CuCO3 decomposes on heating to form one of these oxides and an equation can be written for each possible reaction:

Equation 1: 2CuCO3 (s) Cu2O (s) + 2CO2 (g) + ½O2 (g)

Equation 2: CuCO3 (s) CuO (s) + CO2 (g)

Our aim for the investigation is to find out which of the two equations above is correct and which oxide is formed when copper carbonate decomposes. Using the mole theory, an experiment is to be designed to measure the volume of gas, which will hence prove that which is the correct equation for the practical. The students also have to determine the quantities of reagents to be used in the experiment.

Background Information

Copper is a transition metal. It is found abundantly at many locations as a primary mineral in basaltic lavas and also as reduced from copper compounds. Copper pure is very malleable and ductile and can be rolled into sheets, hammered into thin leaves, and drawn into wire. It is an excellent conductor of heat and electricity. Some of its physical and chemical properties are given below:

It is extracted by reduction on heating with carbon from its oxide ores and its carbonate ores (e.g. malachite) and by smelting from its sulphide ores (e.g. copper pyrites).

Copper and is a chief constituent in many alloys such as brass, bronze and nickel silvers. It is widely used in the electrical industry, in cooking utensils and in brewing vats and in boilers and fireboxes in locomotives and steam engines.

Basic copper carbonates are formed when an alkaline carbonate is added to the solution of a copper salt. These compounds have a bright blue or green colour and ...