THSB
Substances, Chemical Reactions, and Conservation of Matter
Item SC043005: When baking soda and lemon juice react in a sealed plastic bag, the weight will not change because the number of each kind of atom does not change.
A student places some baking soda and a jar of lemon juice in a plastic bag and seals the bag. She weighs the bag and everything in it. She shakes the bag so that the lemon juice spills out of the jar and mixes with the baking soda inside the bag. The student observes that bubbles form, and the bag expands.
If the student weighs the bag and everything in it after the bubbling stops and compares the final weight to the starting weight, what will she find out?
- The final weight will be greater than the starting weight because new atoms are produced during the experiment.
- The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment.
- The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment.
- The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment.
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 375 |
6–8 n = 375 |
9–12 n = 0 |
Male n = 205 |
Female n = 170 |
English n = 347 |
Other n = 28 |
||
| A. | The final weight will be greater than the starting weight because new atoms are produced during the experiment. | 24% | 24% | NAN% | 22% | 26% | 24% | 25% |
| B. | The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment. | 16% | 16% | NAN% | 14% | 19% | 15% | 29% |
| C. | The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment. | 41% | 41% | NAN% | 46% | 36% | 43% | 21% |
| D. | The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment. | 18% | 18% | NAN% | 18% | 19% | 18% | 25% |
Post-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 376 |
6–8 n = 376 |
9–12 n = 0 |
Male n = 206 |
Female n = 170 |
English n = 349 |
Other n = 27 |
||
| A. | The final weight will be greater than the starting weight because new atoms are produced during the experiment. | 16% | 16% | NAN% | 15% | 17% | 14% | 41% |
| B. | The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment. | 6% | 6% | NAN% | 4% | 8% | 5% | 11% |
| C. | The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment. | 72% | 72% | NAN% | 75% | 68% | 75% | 30% |
| D. | The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment. | 6% | 6% | NAN% | 6% | 7% | 5% | 19% |