The Decomposition of Copper Carbonate

The Decomposition of Copper Carbonate

Copper has two oxides, Cu2O, and CuO. 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) [IMAGE] Cu2O (s) + 2CO2 (g) + 1/2O2

(g)

Equation 2: CuCO3 (s) [IMAGE] CuO (s) + CO2 (g)

The aim of this investigation is to prove which of these two equations

is correct.

From the equations above we can see that in both reactions gas is

evolved and by collecting the volume of gas produced we can accurately

say which reaction is taking place.

To find which equation is correct, we can use ideas about the mole and

the volume one mole of gas occupies at standard conditions.

Background Information

Basic copper carbonate occurs in nature as the mineral malachite (CuCO3)

it can be synthesised in the laboratory regardless of its source;

basic copper carbonate has the same composition (CuCO3). Copper

carbonate is a green powder. When heated it decomposes to give a black

colour of copper oxide and the reaction releases carbon dioxide. When

it is heated, CuCO3 splits up or decomposes. When one substance splits

up into two or more on heating, this is called "thermal

decomposition". The carbon dioxide gas formed is lost to the air or

collected, so the copper carbonate loses mass the copper oxide formed

weighs less than the copper carbonate. However, the mass of copper

carbonate equals the total mass of the copper oxide and carbon dioxide

because the same atoms are present but in different ways.

It is possible to determine which equation is correct by measuring the

volume of...

... middle of paper ...

...ume produce by equation 1, i.e. 18.5cm3) this would

indicate that less gas has been produced, and thus suggest equation 2

is correct.

The most probable equation to be proved correct is equation 2 because

as Oxygen is needed for the reaction and the products are oxides,

Oxygen cannot itself be released during combustion reactions, as

indicated in the 'Oxford Dictionary of Chemistry'. Oxygen cannot be

produced as a product, therefore we can disprove equation 1.

Bibliography

During my investigation I made use of the following resources:

* Chemistry 1, B Ratcliff, H Eccles, D Johnson, J Nicholson, J

Raffan

* Hazcard references taken from the school network

* The website http://dwb.unl.edu/chemistry/microscale/mscale16.html

* Personal class notes

* The Oxford Dictionary of Chemistry