During a science festival, a student heats a small sample of copper carbonate in a test tube. Fig. 1 shows the apparatus before heating. The gas produced is...
Question 1 Report
During a science festival, a student heats a small sample of copper carbonate in a test tube. Fig. 1 shows the apparatus before heating. The gas produced is passed into limewater. The student observes a black solid in the tube and cloudy limewater. This allows the student to identify the products of a thermal decomposition reaction.
(a) Name the black solid formed. [1]
(b) Describe the test for the gas produced. [2]
(c) Complete the word equation: copper carbonate → copper oxide + _____. [1]
(d) Explain why this is not a displacement reaction. [1]
Answer Details
(a) The black solid is copper oxide. [1]
(b) Bubble the gas through limewater. [1] The limewater turns cloudy or milky, identifying carbon dioxide. [1]
(c) \[\text{copper carbonate} \rightarrow \text{copper oxide} + \text{carbon dioxide}\] The missing product is carbon dioxide. [1]
(d) This is thermal decomposition because one compound breaks down when heated. It is not displacement, which requires one element to replace another element in a compound. [1]
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