To determine the most likely identity of Marjorie's unknown substance, we can analyze the provided data about density, boiling point, and solubility characteristics of the substances.
Characteristics of the Unknown Substance:
- Density: approximately 2.2 g/mL
- Solubility in Water: No information given, but we can infer based on the choices.
- Solubility in CCl4: insoluble
Evaluation of Possible Substances:
-
NaCl
- Density: 2.165 g/mL (close to 2.2 g/mL)
- Solubility in CCl4: insoluble
- Solubility in water: soluble
- Boiling Point: 1413°C (not an issue)
-
C10H8
- Density: 1.14 g/mL (not close to 2.2 g/mL)
- Solubility in CCl4: soluble (not a match)
- Solubility in water: insoluble
-
FeCl3
- Density: 2.898 g/mL (higher than 2.2 g/mL)
- Solubility in CCl4: insoluble (matches)
- Solubility in water: soluble
-
SiO2
- Density: 2.634 g/mL (higher than 2.2 g/mL)
- Solubility in CCl4: insoluble (matches)
- Solubility in water: insoluble
Conclusion:
From the analysis:
- Both NaCl and SiO2 have a density close (but not exact) to 2.2 g/mL and are insoluble in CCl4.
- However, NaCl is soluble in water while SiO2 is insoluble in water, leaving NaCl as more likely in normal conditions.
- FeCl3 has a density too high and C10H8 has a much lower density, which eliminates them as possible candidates.
Given the only proper match for Marjorie's unknown substance based on the provided characteristics, the best option based on density and solubility, while also noting that NaCl would not typically be tested for CCl4 solubility for a definitive result:
The most likely identity of Marjorie's unknown substance is: A. NaCl
2 answers