An air-quality scientist uses a heat-resistant ceramic filter to collect soot from polluted air. The scientist heats the filter strongly in a plentiful supply of oxygen until its mass no longer changes.
| Stage | Mass of filter and contents in g |
|---|---|
| Before collecting soot | 12.684 |
| After collecting soot | 12.699 |
| After heating in oxygen | 12.684 |
Use the results to explain why the mass of the filter returned to its original value after heating. In your answer, identify the substance in soot and the gaseous product formed.
102 exam-style questions on AQA GCSE Chemistry 9.3 Common atmospheric pollutants and their sources, covering 9.3.1 Atmospheric pollutants from fuels and 9.3.2 Properties and effects of atmospheric pollutants. Each one has a worked solution and a mark scheme showing where the marks go.