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 SB066001: Two liquids undergo a chemical reaction in an open jar and bubbles form. The mass of the liquids is less after the reaction because a gas was produced and that gas left the system.
A student has two different liquids in open jars. She measures the mass of the liquids. Then she pours the liquid from one jar into the other jar, and she observes bubbles. After the bubbling stops, she measures the mass of the liquids again and finds that the mass of the liquids is now less than the mass of the liquids before they were mixed together.
How can her observation be explained?
- A chemical reaction occurred and the mass always decreases during a chemical reaction.
- A gas was produced during the chemical reaction and gases have less mass than liquids.
- A gas was produced during the chemical reaction and gases can leave an open container like the jars.
- Matter was destroyed during the chemical reaction and mass is a measure of the amount of matter.
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
|||
|---|---|---|---|---|---|---|---|
| n = 371 |
6–8 n = 371 |
9–12 n = 0 |
Male n = 204 |
Female n = 167 |
English n = 343 |
Other n = 28 |
|
| A. | 13% | 13% | NAN% | 12% | 14% | 13% | 21% |
| B. | 15% | 15% | NAN% | 14% | 16% | 15% | 18% |
| C. | 62% | 62% | NAN% | 64% | 59% | 63% | 46% |
| D. | 10% | 10% | NAN% | 9% | 10% | 9% | 14% |
Post-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
|||
|---|---|---|---|---|---|---|---|
| n = 369 |
6–8 n = 369 |
9–12 n = 0 |
Male n = 204 |
Female n = 165 |
English n = 341 |
Other n = 28 |
|
| A. | 7% | 7% | NAN% | 8% | 5% | 6% | 7% |
| B. | 7% | 7% | NAN% | 7% | 7% | 6% | 18% |
| C. | 84% | 84% | NAN% | 84% | 84% | 85% | 68% |
| D. | 2% | 2% | NAN% | 1% | 4% | 2% | 7% |