Gravimetric Analysis for H2 Chemistry Paper 4: Volatilisation, Constant Mass, and ACE Errors
01 May 2026, 00:00 Z
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Q: What does H2 Chemistry gravimetric analysis test?
A: It tests whether you can use mass change to determine composition or purity, while controlling heating, cooling, weighing, and constant-mass technique.
TL;DR
In volatilisation gravimetry, a sample is heated so a volatile component leaves. The remaining solid is cooled and weighed repeatedly until constant mass is reached. Paper 4 marks come from the method as much as the calculation: heat gently at first, cool before weighing, repeat until mass change is negligible, and explain how incomplete decomposition, moisture uptake, or solid loss affects the result.
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Status: SEAB H2 Chemistry 9476 syllabus checked 2026-05-01. The syllabus lists gravimetric analysis, including volatilisation gravimetry, in the Practical Assessment scope. Actual yearly apparatus requirements still depend on Confidential Instructions, so treat this as preparation for a technique family, not a prediction.
1 | What Gravimetric Analysis Means
Gravimetric analysis uses mass to infer an amount of substance. In H2 Chemistry Paper 4, the task may be practical, data-based, or a planning and evaluation context.
The common school-lab pattern is volatilisation gravimetry:
- Measure the mass of an empty container.
- Add the sample and measure the combined mass.
- Heat the sample so a volatile component leaves.
- Cool the container.
- Reweigh.
- Repeat heating, cooling, and weighing until the mass is constant.
The chemistry could involve water of crystallisation leaving a hydrated salt, a carbonate decomposing, or a volatile impurity being removed. The exact reaction matters less than the discipline of mass measurement.
2 | Volatilisation vs Precipitation Gravimetry
| Type | What changes | Common data outcome | Paper 4 risk |
