States of Matter & Gases — Extension · Physical Science: Chemistry, Grade 11
Relate particle motion, attractions, gas models, and phase-change energy.
Heating-Curve Energy Budget
Investigate
Which stages consume the most energy in a water-heating model?
Use two dedicated sessions: first define the model, boundary, variables and comparison, then collect suitable records or analyze the complete supplied-data route; second complete calculations/graphs, compare alternatives, revise and prepare the report. Extend collection time where needed. Supplied-data work does not certify supervised laboratory minutes or mandated investigations.
Materials
- Provided temperature/energy table
- Graph paper or spreadsheet,calculator
Before you begin
Use only the listed household materials or analyze the supplied data. An adult should review setup. No flames, strong acids/alkalis, unknown chemicals, household mains, radiation sources, or high-speed projectiles are needed. Keep food-study materials separate from eating and wash hands afterward.
Plan a fair test
Track a 10 g pure-water sample at 1atm; added energy is modeled without heat loss.
Method
- Write a prediction and the physical/chemical mechanism behind it.
- Draw the setup or system boundary; label variables and units.
- Graph temperature versus cumulative energy with phase labels.
- UseLf=334 J/g andcwater=4.18 J/g°C to calculate each stage.
- Compare plateau energy with temperature-rise energy and discuss real heat loss.
- Record repeated observations where possible; keep original readings and note resolution or uncertainty.
- Write a claim supported by specific numbers, explain the mechanism, and identify one limitation and a next test.
Example data — for analysis when materials are unavailable
Illustrative teaching data, not measurements from a real district laboratory. Analyze these when materials are unavailable and identify them as provided data. Do not claim to have performed a measurement you did not make.
| Stage | Temperature(°C) | Cumulative added energy(J) |
|---|---|---|
| Ice just melting | 0 | 0 |
| Melt completed | 0 | 3340 |
| Water at 20°C | 20 | 4176 |
Analyze and explain
- Find energy for melting versus warming.
- Explain why a horizontal graph section can have changing energy.
- What would a warming sensor away from the sample miss?
- Link the pattern to a labeled particle, structure, energy or amount model from the chapter.
- Distinguish supplied illustrative records from measurements actually collected.
- Identify uncertainty and propose a comparison that would test an alternative explanation.
What a strong explanation includes
- A stated prediction, conditions, and controlled variables or explicit model boundary.
- A labeled table/graph with units, calculations, and attention to repeated values or uncertainty.
- A claim citing numerical evidence and a scientifically accurate mechanism.
- A limitation, alternative explanation, and useful follow-up test.
- Preserve initial reasoning and an evidence-supported revision.
- Check units, species identity, system boundary and physical assumptions.
Parent / teacher guide: discuss after the investigation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Compare this model with the learner’s actual evidence. Different measurements can support a different conclusion; check the reasoning and limitations, not matching wording.
Extend the chapter investigation by evaluating its evidence and proposing a better test.
Problem 1
Answer and explanation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Problem 2
Answer and explanation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Problem 3
Answer and explanation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Problem 4
Answer and explanation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Problem 5
Answer and explanation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Problem 6
Answer and explanation
Melting takes 3340 J; warming liquid takes 836 J; total 4176 J. The plateau represents phase rearrangement energy. Real equipment loses heat and may have sensor gradients, so measured input can exceed the ideal amount. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.