Gas Volume & Stoichiometry Investigations for H2 Chemistry Paper 4
Download printable cheat-sheet (CC-BY 4.0)17 Nov 2025, 00:00 Z
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Q: What does Gas Volume & Stoichiometry Investigations for H2 Chemistry Paper 4 cover?
A: Everything needed to run leak-free gas-syringe, inverted burette, and balance-based investigations-apparatus setup, MMO routines, spreadsheet-ready PDO tables, and ACE commentary prompts anchored to SEAB’s 2026 H2 Chemistry Paper 4 (9729) practical guidance.
TL;DR
Paper 4 (2 h 30 min, 55 marks; Planning 5%, MMO/PDO/ACE 15% per SEAB 9729) devotes 20 percent of the H2 grade to practical skills, and gas measurements frequently partner kinetics or redox contexts.
Master leak checks, temperature logging, and spreadsheet conversions so volume–time or mass-loss data lead to defendable stoichiometric conclusions under exam timing.
Log this investigation alongside the rest of your Paper 4 practice set in our H2 Chemistry Experiments hub.
Status: SEAB H2 Chemistry (9729, first exam 2026) syllabus last checked 2025-11-29 (PDF last modified 2024-07-17). Paper 4 remains 2 h 30 min, 55 marks, weighted at 20 % with Planning at 5 % and MMO/PDO/ACE at 15 % combined.
1 | Where gas investigations sit in Paper 4
- The SEAB 2026 H2 Chemistry syllabus (9729) lists gas collection among the expected Paper 4 techniques (Practical Assessment section: “Gas collection”) and weights the paper at 2 h 30 min, 55 marks with Planning at five percent and MMO/PDO/ACE at fifteen percent.
- Specimen Paper 4 tasks from Cambridge/SEAB typically pair gas collection with stoichiometric deductions (e.g., magnesium with acid, catalytic decomposition of hydrogen peroxide, or thermal decomposition of carbonates).
- The 2026 SEAB specimen paper for 9476 Chemistry Paper 4 includes a gas-volume investigation that mirrors this workflow-2 h 30 min duration, Planning carried via pre-lab prompts, and MMO/PDO grids requiring precise volume logging.
- Expect to justify the apparatus you choose, state how you record temperature/pressure, and describe how the data will be processed to obtain molar conclusions.
2 | Apparatus selection and setup discipline
| Technique | Strengths | Limitations |
