Calcium carbonate is strongly heated until it undergoes thermal decomposition to form calcium oxide and carbon dioxide. The calcium oxide (unslaked lime) is dissolved in water to form calcium hydroxide (limewater). Bubbling carbon dioxide through this forms a milky suspension of calcium carbonate Show This experiment can be carried out conveniently in groups of two or three and takes about 40–45 minutes. EquipmentApparatus
Apparatus notes
Chemicals
Health, safety and technical notes
Procedure
Teaching notesKeep an eye on less mature students who might be tempted to suck rather than blow through the filtrate. The results expected are as follows:
This set of experiments involves a variety of important reactions and types of reactions, with several references to industrial processes. The roasting of limestone and the hydration of the quicklime formed has relevance in the manufacture of plaster and cement, and in the laboratory limewater is a common reagent for the testing of carbon dioxide. Students could be asked to carry out web research on these applications. Some question and answers for the class after the experiment
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