Question
Marjorie is trying to determine the identity of an unknown substance. After running tests, she determines that the substance is insoluble in CCl4 with a density of about 2.2 g/mL.
Substance Density Boiling Point Solubility (in water) Solubility (in CCl4)
NaCl 2.165 g/mL 1413°C soluble insoluble
C10H8 1.14 g/mL 255°C insoluble soluble
FeCl3 2.898 g/mL 315°C soluble insoluble
SiO2 2.634 g/mL 2590°C insoluble insoluble
Using the data above, which of the following substances is most likely Marjorie's unknown?
A.
FeCl3
B.
NaCl
C.
C10H8
D.
SiO2
Substance Density Boiling Point Solubility (in water) Solubility (in CCl4)
NaCl 2.165 g/mL 1413°C soluble insoluble
C10H8 1.14 g/mL 255°C insoluble soluble
FeCl3 2.898 g/mL 315°C soluble insoluble
SiO2 2.634 g/mL 2590°C insoluble insoluble
Using the data above, which of the following substances is most likely Marjorie's unknown?
A.
FeCl3
B.
NaCl
C.
C10H8
D.
SiO2
Answers
GPT-4o mini
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:
1. **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)
2. **C10H8**
- Density: 1.14 g/mL (not close to 2.2 g/mL)
- Solubility in CCl4: soluble (not a match)
- Solubility in water: insoluble
3. **FeCl3**
- Density: 2.898 g/mL (higher than 2.2 g/mL)
- Solubility in CCl4: insoluble (matches)
- Solubility in water: soluble
4. **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**
### 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:
1. **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)
2. **C10H8**
- Density: 1.14 g/mL (not close to 2.2 g/mL)
- Solubility in CCl4: soluble (not a match)
- Solubility in water: insoluble
3. **FeCl3**
- Density: 2.898 g/mL (higher than 2.2 g/mL)
- Solubility in CCl4: insoluble (matches)
- Solubility in water: soluble
4. **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**