Carbon dioxide and global warming: the greenhouse effect
3 marks · EasyA student heated zinc carbonate in a test tube to produce carbon dioxide gas.
Write a balanced chemical equation, including state symbols, for this reaction.
Name the type of reaction taking place when zinc carbonate breaks down on heating.
State what you would observe inside the test tube as the reaction proceeds.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) \ce{ZnCO3(s) -> ZnO(s) + CO2(g)}
(b) Thermal decomposition
(c) The solid in the test tube changes from white to yellow · must show Observation must mention colour change (white to yellow)
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Marking points
A1 (a) · 1 mark · Correct balanced equation with state symbols: \ce{ZnCO3(s) -> ZnO(s) + CO2(g)}
B1 (b) · 1 mark · Names the reaction as 'thermal decomposition'
B1 (c) · 1 mark · Mentions correct observation for this reaction (colour change from white to yellow or similar)
Worked solution
a) Balanced equation:
b) Type of reaction: Thermal decomposition
c) Observation: The solid changes from white (zinc carbonate) to yellow (zinc oxide) as it is heated.