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Checking Particle Identity After Heating 4 questions
Checking Particle Identity After Heating
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A classroom model heats two solids in separate sealed containers. Each begins with just one kind of molecule in its solid sample. The display identifies particles in the solid and in any gas that appears. Each container is then cooled to its starting temperature.
| Sample | Molecules before heating | Molecules in gas during heating | Particles present after cooling |
|---|---|---|---|
| P | AB2 | AB2 | AB2 only |
| Q | CD2 | D2 | C and D2 |
Question 1
Which gas record can be explained by intact molecules moving apart and entering the gas phase?
- P only
- Q only
- Both records
- Neither record
Question 2
Use both records to explain why seeing a gas is insufficient to identify a chemical change.
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A repeat starts with 12 CD2 molecules. Every CD2 breaks into one C particle and one D2 molecule in this model. The container stays sealed.
Question 3
Predict the number of D₂ molecules after the repeat and compare the total number of D atoms before and after.
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Question 4
A student says that because the D atom count is unchanged, the process must be a physical change. Evaluate the claim.
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