Enthalpy & Calorimetry Investigations for H2 Chemistry Paper 4

Q: What does Enthalpy & Calorimetry Investigations for H2 Chemistry Paper 4 cover?
A: A step-by-step thermochemistry routine for Paper 4-planning insulation, logging temperature data with probes, linearising cooling curves, and writing ACE commentary that meets MOE’s 2025 assessment expectations.

TL;DR
Paper 4 lasts 2 h 30 min, carries 50 marks, and contributes 20 % of the H2 Chemistry grade. Thermochemistry investigations (solution, neutralisation, combustion, thermometric titration) are flagged as recurring contexts in MOE’s 2025 practical brief.
Calibrate probes, insulate reaction vessels, capture temperature-time data for extrapolated ΔT, and automate q = mcΔT calculations so ACE discussion focuses on heat losses, assumptions, and realistic refinements.

1 | Why thermochemistry stays in rotation

• The MOE 2025 Pre-University Chemistry syllabus positions Paper 4 as a 2 h 30 min, 50-mark practical assessing Planning (P), MMO, PDO, and ACE across recurring contexts that include thermochemistry and thermometric titration.
• Candidates often see solution/neutralisation calorimetry, dissolution enthalpy, combustion surrogates (spirit burner or copper calorimeter), or Hess’ Law cycles with temperature data.
• Each scenario tests: insulation planning, precise temperature measurement, quick spreadsheet processing, and evaluation of heat losses plus assumption limits (constant specific heat, negligible calorimeter heat capacity).

2 | Planning for controlled energy transfers

Set up planning statements around:

• Aim and enthalpy target - specify whether you are determining ΔH_neut, ΔH_soln, or ΔH_comb, including the stoichiometric basis (per mole of water produced, solute dissolved, or fuel burned).
• Controlled variables - match MOE guidance by fixing reagent concentrations, initial temperatures, solution volumes, and stirring method; justify insulation choice (double polystyrene cup, lid, thermometer collar).
• Measurement strategy - note apparatus accuracy (probe resolution ±0.1 °C, balance ±0.01 g), pre-log baseline temperatures, and planned data logging interval (e.g., every second with a digital probe).
• Risk assessment - cite PPE (gloves, goggles), handling of hot liquids, corrosive acids/bases, and flammable fuels. Flag heat-related hazards before mixing or burning starts.
• Data application - outline how temperature-time points will feed into extrapolated ΔT, enthalpy calculations, and uncertainty analysis.

3 | MMO routines for reliable temperature capture