Original Project
Substances, Chemical Reactions, and Conservation of Matter
Item SC092004: When a liquid changes to a gas in a sealed container and the number of atoms stays the same, the mass of the jar and everything in it also stays the same.
A student placed a liquid in a jar and sealed it. Then she heated the liquid and it turned into a gas. If the number of atoms in the sealed jar stayed the same, what happened to the mass of the jar and everything inside it after she heated it?
- The mass increased.
- The mass decreased.
- The mass stayed the same.
- It depends on whether a chemical reaction occurred.
- Distribution of Responses
- Students Responding Correctly
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 1033 | 2742 | 38% |
| Grades | |||
| 6–8 | 555 | 1626 | 34% |
| 9–12 | 469 | 1094 | 43% |
| Gender | |||
| Male | 528 | 1307 | 40% |
| Female | 476 | 1379 | 35% |
| Primary Language | |||
| English | 919 | 2403 | 38% |
| Other | 78 | 267 | 29% |
- Disciplinary Core Ideas
- PS1.B Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.
PS1.B The total number of each type of atom is conserved, and thus the mass does not change.