CALCULATORS / PROCESS AND CHEMICAL ENGINEERING ESTIMATES

Steady material balance calculator

Steady mass flow balance with one outlet; no accumulation or reaction.

chemistry-mass-balance.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

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

Scenario	outletkg/s
	2.9
	2.5

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.

output target2.90 kg/s✓ passes

BASELINE INPUTS

inletA2 kg/sinletB1 kg/sloss0.1 kg/s

CALCULATED

outlet2.9 kg/s

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Steady material balance
# Scope: Steady mass flow balance with one outlet; no accumulation or reaction.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

inletA = 2 kg/s
inletB = 1 kg/s
loss = 0.1 kg/s

outlet := inletA+inletB-loss [kg/s]

check output target: outlet >= 2.5 kg/s

scenario alternative: inletA = 1.6 kg/s

Calculated from your source · not saved

Baseline · Baseline

output target2.90 kg/s ✓ passes

alternative · alternative

output target2.50 kg/s ✓ 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.

outlet: outlet = inletA+inletB-loss [kg/s]

Original worked example

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

Given

inlet a: 2 kg/s
inlet b: 1 kg/s
loss: 0.1 kg/s

Calculated

outlet: 2.9 kg/s

Assumptions and limits

Steady mass flow balance with one outlet; no accumulation or reaction.

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: Steady material balance. Inputs: inlet/outlet streams; compositions; accumulation assumption. Outputs: missing stream or composition. 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: inlet/outlet streams, compositions, accumulation assumption
Outputs: missing stream or composition
Modes: calculate, compare, sweep
Drawing: Process balance diagram

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