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CALCULATORS / PROCESS AND CHEMICAL ENGINEERING ESTIMATES

Ideal-gas state calculation calculator

Ideal gas law with absolute pressure/temperature; no real gas correction.

chemistry-ideal-gas.napkin / editable
✓ checks pass

SCENARIO COMPARISON

Compare the numbers.

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

ScenariopressurekPa
99.7736
79.8188

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.

pressure budget99.77 kPa✓ passes

BASELINE INPUTS

CALCULATED

pressure99.774 kPa

Edits change the baseline source.

Calculated from your source · not saved
Baseline · Baseline
pressure budget99.77 kPa ✓ passes
alternative · alternative
pressure budget79.82 kPa ✓ 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.

pressure
pressure = amount*gasConstant*temperature/volume [kPa]

Original worked example

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

Given

amount
1 mol
temperature
300 K
volume
0.025 m^3
gas constant
8.31446 J/(mol*K)

Calculated

pressure
99.7736 kPa

Assumptions and limits

Ideal gas law with absolute pressure/temperature; no real gas correction.

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: Ideal-gas state calculation. Inputs: pressure; volume; amount; temperature. Outputs: missing ideal-gas state variable. 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: pressure, volume, amount, temperature
  • Outputs: missing ideal-gas state variable
  • Modes: calculate, compare, sweep
  • Drawing: Process balance diagram

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

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