A chemist investigates the thermal decomposition of a sample of sodium hydrogencarbonate, NaHCO3\text{NaHCO}_3NaHCO3, in an open test tube. The chemist records the total mass of the test tube and its contents at two-minute intervals, obtaining the following data:
| Time (minutes) | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|
| Mass of tube and contents (g) | 45.32 | 43.15 | 41.56 | 40.21 | 39.12 | 38.35 | 37.78 |
Explain why it cannot be concluded from this dataset that the decomposition reaction has gone to completion.
258 exam-style questions on Edexcel GCSE Chemistry Calculations involving masses. Each one has a worked solution and a mark scheme showing where the marks go.