SCIENCE · INVESTIGATE AND EXPLAIN

Infer dissolved gas from its own partial-pressure constraint

Solubility is an equilibrium composition under specified conditions.

Learning outcome: Compare(200 kPa,.20) with(100 kPa,.40), then compare fixed total pressure at two fractions. Retain partial pressure and equilibrium concentration; identify the held-fixed temperature and solvent.

Starting recap

Use chemical amount, dimensional ratios and positive interval endpoints. Distinguish original formula units, independently moving species and a chosen thermodynamic standard.

All lessons are open directly. Your saved experiments remain when you leave and return.

Try

At total200 kPa and gas solute fraction.20, solute partial pressure40 kPa gives c=2×10⁻5×40=.000800 M.

Open the experiment

Predict

Will raising total pressure with an inert gas necessarily raise dissolved solute concentration?

Your prediction and reason

Experiment

Compare(200 kPa,.20) with(100 kPa,.40), then compare fixed total pressure at two fractions. Retain partial pressure and equilibrium concentration; identify the held-fixed temperature and solvent.

Use solute partial pressure rather than total pressure

Worked teaching model · synthetic values · Dilute nonreacting gas at fixed temperature; c=kH*p with supplied kH=2.0×10⁻5 mol/(L kPa). Ideal gas partial pressure yP; equilibrium with a large reservoir. Henry constants have multiple reciprocal conventions; this one has explicitly stated units. No gas dissolution kinetics or pressurized apparatus.

Gas total pressure: 200 kPa Gas-phase solute mole fraction: 0.2 fraction

Reset keeps your prediction, captures and practice history.

Axes rescale. Connected samples represent declared equilibrium or activity relationships, not elapsed time. Dashed lines show the concentration-scale gamma=1 reference or ideal Raoult total pressure as named in the model.

Numerical diagram coordinates

total reservoir pressure (kPa)	equilibrium dissolved solute (mol/L)
0	0
10	4.000000e-5
20	8.000000e-5
30	0.00012
40	0.00016
50	0.0002
60	0.00024
70	0.00028
80	0.00032
90	0.00036
100	0.0004
110	0.00044
120	0.00048
130	0.00052
140	0.00056
150	0.0006
160	0.00064
170	0.00068
180	0.00072
190	0.00076
200	0.0008
210	0.00084
220	0.00088
230	0.00092
240	0.00096
250	0.001
260	0.00104
270	0.00108
280	0.00112
290	0.00116
300	0.0012

Calculated evidence under the stated assumptions
Quantity	Value	Unit
Solute partial pressure	40	kPa
Equilibrium dissolved concentration	0.0008	mol/L
Incorrect total-pressure inference	0.004	mol/L

Gas identity, temperature and its own partial pressure set the stated equilibrium concentration.

An inert-gas addition at constant solute partial pressure does not change this ideal-dilute prediction, even if total pressure rises. The coefficient is temperature- and solvent-dependent and its reciprocal is also called a Henry constant in other conventions. Stirring changes approach rates, not this equilibrium relation; reactive gases require additional chemistry.

Retain the species, standard state and ideal/nonideal assumptions with every number. This mathematical packet is not a solution-preparation procedure or evidence of observed laboratory technique.

Gas identity, temperature and its own partial pressure set the stated equilibrium concentration.

Observation to attach to a capture

Captures preserve recipes and replay their calculated results. They are synthetic model evidence, not physical measurements.

Understand

Separate equilibrium from the approach to it

Solubility is an equilibrium composition under specified conditions. Stirring can change how rapidly a system approaches that composition without changing the equilibrium relation. A temporarily supersaturated state can persist; observing dissolved material does not by itself prove equilibrium.

Declare the Henry convention

This model uses c=kH p with kH=2.0×10⁻5 mol/(L kPa), fixed temperature and a nonreacting dilute gas. Other references use a reciprocal coefficient or a mole-fraction convention, so the name Henry constant alone does not fix the units. Write the equation as well as the numerical coefficient.

Use the right pressure

In an ideal gas reservoir the solute partial pressure is yP. Total200 kPa and solute fraction.20 give40 kPa and dissolved concentration.000800 M. Using total pressure would give.00400 M, five times too large. The reservoir is large enough that dissolution does not appreciably change its composition in this model.

Construct a controlled counterexample

Total100 kPa with fraction.40 also gives40 kPa and the same predicted concentration. Adding inert gas while preserving the solute partial pressure therefore does not change this ideal-dilute result. At fixed gas fraction, increasing total pressure does increase the solute partial pressure. These are different interventions, not contradictory laws.

Transfer and identify limits

At total250 kPa and fraction.30, predict75 kPa and.00150 M. If the liquid warms, the old coefficient is no longer automatically valid; many gases become less soluble on warming, but the actual coefficient requires temperature-specific evidence. Reactive gases require chemical equilibria beyond this simple dissolution account. No pressurized gas or real dissolution experiment is requested.

Sources and evidence boundary

Conceptual references checked 30 October 2026: Solubility and Henry law. All cases, prose and diagrams are original. Supplied and calculated data are not observed laboratory evidence. No chemical handling, heating, pressurized gas, membrane experiment or clinical application is requested. Retain predictions, contrasting recipes and a changed-case explanation; numerical agreement does not certify independent mastery.

Apply

Public practice checks a specific claim. It does not establish independent mastery.

Why does faster mixing not prove that an equilibrium solubility constant changed?

Your explanation and limitations

Continue

Completion requires a saved prediction, at least one capture and a reflection. Presence checks do not grade your reasoning.

Skipping retains experiments and awards no mastery.

Previous: Test ideal and nonideal vapor-composition predictions Next: Connect two phase shifts to one effective particle account

Save a science backup or import one

Science work is stored locally in this browser, separately from mathematics and AI. It does not sync automatically. Use this science-only backup; this checkout's older all-subject export does not include science.

A legacy file is available only when the complete snapshot fits the 36 MB limit. For larger snapshots, prepare a complete file set below; never discard notebooks to make a smaller file.

Choose a science backup (maximum 36 MB)

Matching imported notebook drafts replace their current drafts. Omitted lessons and known first attempts remain. Export your current work first if you want to retain both drafts.

Complete file sets and course backups

A file set can hold more work than one science file. Keep its manifest and every part together. Each file is limited to 36 MB. This format needs this version of LearnAI or a compatible newer version; older versions can use only the legacy single-file backup above.

Export scope

The set includes every saved science course and global continuation at this moment. Later edits need a new export. A conflicting tab exports its own visible work, which may differ from saved work in another tab.

Choose the manifest and all parts together

0 file(s) selected. File order and filenames do not determine identity. Missing, changed or conflicting parts block the entire restore; no good part is applied by itself.

Science storage: loading. No account or remote computation is required.