Track matter in a closed model
See this course’s project requirements
A particle-model notebook explaining states, mixtures, elements, compounds, mass conservation and a physical separation plan from supplied materials.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Separate measurements from particle explanations.
- Compare solid, liquid and gas models without inflating individual particles.
- Classify all supplied element, compound and mixture drawings.
- Name state transitions while preserving substance identity.
- Balance the supplied closed-system mass stores.
- Choose paper separation methods by recovery goal and complete changed cases.
Review and revise
Use these criteria to check your work and choose what to improve.
- Method: applies the course-specific rules to the supplied cases with visible intermediate work.
- Accuracy: results agree with the stated facts, units, boundaries and independent checks.
- Reasoning: explains why the result follows and identifies a limitation or unresolved question.
- Transfer: completes changed cases and revises the final project when a relevant assumption changes.
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The idea in everyday life
Fictional sealed vessel: container mass 40 g; initially 100 g liquid water and 0 g vapor in this simplified accounting. Later 90 g liquid and 10 g water vapor. The entire vessel remains sealed; condensation on internal surfaces is included with its water store if present.
For a closed model with no matter entering or leaving, total mass remains accounted for across a physical change. Gas counts as matter. A smaller liquid reading can mean matter moved to another part of the system; it is not proof that matter was destroyed. State the measurement boundary before comparing masses.
Track matter in a closed model — worked practice
For a closed model with no matter entering or leaving, total mass remains accounted for across a physical change. Gas counts as matter. A smaller liquid reading can mean matter moved to another part of the system; it is not proof that matter was destroyed. State the measurement boundary before comparing masses.
Fictional sealed vessel: container mass 40 g; initially 100 g liquid water and 0 g vapor in this simplified accounting. Later 90 g liquid and 10 g water vapor. The entire vessel remains sealed; condensation on internal surfaces is included with its water store if present.
1. 1. Boundary
List everything included in the weighing system.
You should see: Container, liquid and vapor are all inside the same sealed boundary.
2. 2. Initial
Add the initial masses.
You should see: 40+100+0=140 g.
3. 3. Later
Add the later masses and compare.
You should see: 40+90+10=140 g; total is unchanged.
4. 4. Explain
Identify the error in comparing only liquid mass.
You should see: The 10 g moved to the vapor store; omitting it changes the accounting boundary.
What to finish
An initial/later mass table with a boundary statement.
Watch for this
The no-entry/no-exit assumption no longer holds. Remaining vessel mass can fall when matter crosses the boundary without violating conservation.
How can I tell I understand it?
Recalculate changed store amounts without dropping a gas contribution.
Quick knowledge check
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Source & access notes · checked 2026-10-01
Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.
Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.
Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.
Source & access notes · checked 2026-10-01
Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.
Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.
Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.
Source & access notes · checked 2026-10-01
Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.
Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.
Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.
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