THSB
Substances, Chemical Reactions, and Conservation of Matter
Many substances react chemically in predictable ways with other substances to form new substances with different…
Item SC069007: When a chemical reaction occurs, the characteristic properties of the products are different than the characteristic properties of the reactants. (This item used a table to show the properties of the substances.)
A student determines the density, solubility, and boiling point of two liquids, Liquid 1 and Liquid 2. Then he stirs the two liquids together and heats them. After stirring and heating the liquids, two different liquids form, Liquid 3 and Liquid 4. Then the student determines the density, solubility, and boiling point of Liquids 3 and 4. He concludes that a chemical reaction occurred. Here are his results:
| Density (g/mL) | Soluble in Water | Boiling Point (°C) | ||
| Before stirring and heating | Liquid 1 | 0.96 | Yes | 164 |
| Liquid 2 | 0.81 | Yes | 118 | |
| After stirring and heating | Liquid 3 | 0.87 | Yes | 166 |
| Liquid 4 | 1.00 | Yes | 100 | |
How does the student know that a chemical reaction has occurred?
- The student knows that a chemical reaction has occurred because
Liquid 3 has different properties than Liquid 4. - The student knows that a chemical reaction has occurred because
Liquid 1 has different properties than Liquid 2. - The student knows that a chemical reaction has occurred because
Liquids 3 and 4 have different properties than Liquids 1 and 2. - The student knows that a chemical reaction has occurred because
a chemical reaction always occurs when two liquids are mixed together.
(Modified from IQWST)
Pre-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 362 |
6–8 n = 362 |
9–12 n = 0 |
Male n = 201 |
Female n = 161 |
English n = 335 |
Other n = 27 |
||
| A. | The student knows that a chemical reaction has occurred because Liquid 3 has different properties than Liquid 4. |
9% | 9% | NAN% | 11% | 6% | 9% | 15% |
| B. | The student knows that a chemical reaction has occurred because Liquid 1 has different properties than Liquid 2. |
12% | 12% | NAN% | 11% | 12% | 11% | 19% |
| C. | The student knows that a chemical reaction has occurred because Liquids 3 and 4 have different properties than Liquids 1 and 2. |
72% | 72% | NAN% | 72% | 72% | 73% | 56% |
| D. | The student knows that a chemical reaction has occurred because a chemical reaction always occurs when two liquids are mixed together. |
7% | 7% | NAN% | 5% | 9% | 7% | 11% |
Post-Test
Answer Choice |
Overall |
Grades |
Gender |
Primary Language |
||||
|---|---|---|---|---|---|---|---|---|
| n = 361 |
6–8 n = 361 |
9–12 n = 0 |
Male n = 197 |
Female n = 164 |
English n = 333 |
Other n = 28 |
||
| A. | The student knows that a chemical reaction has occurred because Liquid 3 has different properties than Liquid 4. |
6% | 6% | NAN% | 6% | 5% | 5% | 11% |
| B. | The student knows that a chemical reaction has occurred because Liquid 1 has different properties than Liquid 2. |
7% | 7% | NAN% | 9% | 6% | 6% | 21% |
| C. | The student knows that a chemical reaction has occurred because Liquids 3 and 4 have different properties than Liquids 1 and 2. |
80% | 80% | NAN% | 77% | 83% | 81% | 61% |
| D. | The student knows that a chemical reaction has occurred because a chemical reaction always occurs when two liquids are mixed together. |
7% | 7% | NAN% | 8% | 5% | 7% | 7% |