THSB
Substances, Chemical Reactions, and Conservation of Matter
Whenever substances within a closed system interact with one another, the total mass of the system remains the s…
Item SB065001: Mass is conserved when a plant dies in a sealed jar.
A student places a living plant in a jar and seals it so nothing can get in or out. He determines the total mass of the jar and everything inside it. Several weeks later, the plant is dead.
What will happen to the total mass of the jar and everything inside it after the plant dies?
- The mass will decrease because even though there is the same amount of matter in the jar, the matter has less mass because the plant and soil dried out.
- The mass will decrease because matter is destroyed when living things die, so there is less matter in the jar.
- The mass will increase because the plant released gases into the jar when it died, so there is more matter in the jar.
- The mass will stay the same because the jar is sealed, so there is the same amount of matter in the jar.
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 370 |
6–8 n = 370 |
9–12 n = 0 |
Male n = 205 |
Female n = 165 |
English n = 343 |
Other n = 27 |
||
| A. | The mass will decrease because even though there is the same amount of matter in the jar, the matter has less mass because the plant and soil dried out. | 30% | 30% | NAN% | 25% | 36% | 28% | 59% |
| B. | The mass will decrease because matter is destroyed when living things die, so there is less matter in the jar. | 15% | 15% | NAN% | 14% | 17% | 15% | 22% |
| C. | The mass will increase because the plant released gases into the jar when it died, so there is more matter in the jar. | 8% | 8% | NAN% | 9% | 7% | 8% | 4% |
| D. | The mass will stay the same because the jar is sealed, so there is the same amount of matter in the jar. | 46% | 46% | NAN% | 51% | 41% | 49% | 15% |
Post-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 372 |
6–8 n = 372 |
9–12 n = 0 |
Male n = 205 |
Female n = 167 |
English n = 344 |
Other n = 28 |
||
| A. | The mass will decrease because even though there is the same amount of matter in the jar, the matter has less mass because the plant and soil dried out. | 10% | 10% | NAN% | 9% | 12% | 10% | 7% |
| B. | The mass will decrease because matter is destroyed when living things die, so there is less matter in the jar. | 9% | 9% | NAN% | 11% | 8% | 8% | 21% |
| C. | The mass will increase because the plant released gases into the jar when it died, so there is more matter in the jar. | 6% | 6% | NAN% | 5% | 6% | 5% | 11% |
| D. | The mass will stay the same because the jar is sealed, so there is the same amount of matter in the jar. | 75% | 75% | NAN% | 75% | 74% | 76% | 61% |