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CALCULATORS / PROCESS AND CHEMICAL ENGINEERING ESTIMATES

Reaction heat balance calculator

Supplied reaction enthalpy and extent; positive released heat for negative enthalpy.

chemistry-heat-of-reaction.napkin / editable
✓ checks pass

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

ScenarioreleasedkJadiabaticRiseK
10023.8095
8019.0476

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

temperature rise budget23.81 K✓ passes

BASELINE INPUTS

CALCULATED

released100 kJ
adiabaticRise23.81 K

Edits change the baseline source.

Calculated from your source · not saved
Baseline · Baseline
temperature rise budget23.81 K ✓ passes
alternative · alternative
temperature rise budget19.05 K ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

released
released = -extent*enthalpy [kJ]
adiabatic rise
adiabaticRise = released/(mass*heatCapacity) [K]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

extent
2 mol
enthalpy
-50000 J/mol
mass
1 kg
heat capacity
4200 J/(kg*K)

Calculated

released
100 kJ
adiabatic rise
23.8095 K

Assumptions and limits

Supplied reaction enthalpy and extent; positive released heat for negative enthalpy.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Reaction heat balance. Inputs: reaction amount; enthalpy; conversion; heat capacity. Outputs: heat release/absorption; ideal temperature-change estimate. Model scope: Specified chemistry and low-order mass/energy balances. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

  • Inputs: reaction amount, enthalpy, conversion, heat capacity
  • Outputs: heat release/absorption, ideal temperature-change estimate
  • Modes: calculate, compare, sweep
  • Drawing: Process balance diagram

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS

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