Item SC057007: Two solids with the same melting point and color could be the same substance. (This item uses a table that lists properties of the solids.)
A student makes some observations about three solids and summarizes the results in the table below.
| Mass | Melting Point | Color | |
| Solid 1 | 3.0 g | 776°C | white | 
| Solid 2 | 3.0 g | 445°C | white | 
| Solid 3 | 9.8 g | 445°C | white | 
Which of the solids could be the same substance?
- Solids 1 and 2 could be the same substance.
- Solids 2 and 3 could be the same substance.
- All of the solids could be the same substance.
- None of the solids could be the same substance.
				(Modified from IQWST)			
		- Distribution of Responses
 
																- Students Responding Correctly
| Group | Correct | Total | Percent | 
|---|---|---|---|
| Overall | 1211 | 2375 | 51% | 
| Grades | |||
| 6–8 | 582 | 1259 | 46% | 
| 9–12 | 617 | 1095 | 56% | 
| Gender | |||
| Male | 556 | 1105 | 50% | 
| Female | 621 | 1216 | 51% | 
| Primary Language | |||
| English | 1064 | 2079 | 51% | 
| Other | 106 | 224 | 47% | 
- Disciplinary Core Ideas
- PS1.A Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.
- NRC Framework
- Patterns: ...objects can be classified into groups on the basis of similarities of visible or microscopic features or on the basis of similarities of function...

