THSB
Substances, Chemical Reactions, and Conservation of Matter
A pure substance has characteristic properties, such as density, a boiling point, and solubility, all of which a…
Item SB052001: Characteristic properties can be used to identify an unknown solid.
During an activity in science class, a student is given an unidentified white solid. She measures some properties of the solid and lists the properties in the table below.
| Melting point | Soluble in water? | Color | |
| Unidentified solid | 734ºC | yes | white |
Then the teacher gives her the following table that lists the properties for two solids.
| Name of solid (Chemical formula) | Melting point | Soluble in water? | Color |
| Lead Nitrate (Pb(NO3)2) | 270ºC | yes | white |
| Potassium Bromide (KBr) | 734ºC | yes | white |
Could the student’s unidentified solid be either lead nitrate or potassium bromide?
- The unidentified solid could be lead nitrate but not potassium bromide.
- The unidentified solid could be potassium bromide but not lead nitrate.
- The unidentified solid could either be potassium bromide or lead nitrate.
- The unidentified solid could NOT be either potassium bromide or lead nitrate.
- Distribution of Responses
- Points Earned
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 319 | 376 | 85% |
| Grades | |||
| 6–8 | 319 | 376 | 85% |
| 9–12 | N/A | N/A | N/A |
| Gender | |||
| Male | 176 | 206 | 85% |
| Female | 143 | 170 | 84% |
| Primary Language | |||
| English | 300 | 350 | 86% |
| Other | 19 | 26 | 73% |
- Distribution of Responses
- Points Earned
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 334 | 375 | 89% |
| Grades | |||
| 6–8 | 334 | 375 | 89% |
| 9–12 | N/A | N/A | N/A |
| Gender | |||
| Male | 179 | 205 | 87% |
| Female | 155 | 170 | 91% |
| Primary Language | |||
| English | 313 | 348 | 90% |
| Other | 21 | 27 | 78% |