Lab: Thermal Decomposition of Malachite
Malachite is a mineral with the formula Cu2CO3(OH)2(s). When heated, malachite
decomposes to produce copper(II) oxide, carbon dioxide and water vapour.
What is the relationship between the mass of the malachite that is decomposed and the
mass of the copper(II) oxide that is produced?
malachite clay triangle retort stand
crucible Bunsen burner electronic balance
1. Read the entire procedure and construct a data table to record your observations.
2. Carefully weigh a dry empty crucible. Place 2 to 4 g of malachite in the crucible and
reweigh it. Record the weight of the empty crucible and the weight of the crucible
containing the malachite.
3. Set the crucible on a clay triangle supported by an iron ring attached to a retort stand.
Heat with a Bunsen burner for 10 minutes. Be sure that the crucible is in the flame of
4. Allow the crucible and contents to cool to room temperature. Reweigh the crucible
containing the product, CuO(s), and record your data.
Mass of Mass of Mass of
Mass of Crucible +
Crucible + Malachite Copper(II)
Group Crucible Copper(II)
Malachite Reacted Oxide
(g) (g) (g)
1. Write a balanced chemical equation for the thermal decomposition of malachite.
2. Graph the class results with a line graph comparing the mass of the malachite reacted
(independent variable, x-axis) to the mass of the copper(II) oxide produced
(dependent variable, y-axis).
3. Calculate the slope of your line of best fit.
4. Use your graph to predict the mass of copper(II) oxide produced if 120 g of malachite
5. Use your graph to predict the mass of malachite reacted if 300 g of copper(II) oxide
had been produced.