While researching a topic, a student has taken the following notes:
- Refrigerants are chemical compounds used in cooling technologies, such as air conditioners.
- Air conditioners can use refrigerants to absorb heat and release cold air.
- The refrigerant dichloromethane is a hydrochlorocarbon (HCC).
- HCCs are composed of the elements hydrogen, chlorine, and carbon.
- The refrigerant tetradecafluorohexane is a perfluorocarbon (PFC).
- PFCs are composed of fluorine and carbon.
The student wants to contrast dichloromethane and tetradecafluorohexane. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Explanation
Answer: 1) Dichloromethane, a hydrochlorocarbon, is composed of hydrogen, chlorine, and carbon; tetradecafluorohexane, a perfluorocarbon, is composed of fluorine and carbon.
Goal: Contrast the two refrigerants.
Why? Contrasting requires comparing on the same feature. Choice 1 shows different compositions—hydrogen/chlorine/carbon vs. fluorine/carbon.
Traps:
- B) Both are refrigerants → similarity
- C) Both are refrigerants → similarity
- D) Only about one → incomplete