The student wants to specify how the salt enables energy storage. Which choice most effectively uses relevant information from the notes to accomplish this goal?
A
Scientists have developed a freeze-thaw battery that contains molten salt, which liquifies when heated and solidifies at room temperature.
B
The stored energy in a freeze-thaw battery, which contains molten salt, can be used by reheating the battery.
C
When the molten salt in a freeze-thaw battery solidifies at room temperature, energy stops flowing and can be stored in the battery.
D
Molten salt allows a freeze-thaw battery to retain 92% of its charge after twelve weeks.
Explanation
Correct answer: C.
Choice C is the best answer. The sentence specifies how the salt in a freeze-thaw battery enables energy storage, explaining that energy stops flowing and can be stored when the salt solidifies at room temperature.
Why the other choices are wrong
Choice A
Choice A is incorrect. The sentence explains some properties of molten salt; it doesn’t specify how that salt enables energy storage.
Choice B
Choice B is incorrect. The sentence indicates how the energy in a freeze-thaw battery can be released; it doesn’t specify how the salt in the battery enables energy storage.
Choice D
Choice D is incorrect. The sentence specifies how much charge the freeze-thaw battery retains when storing energy; it doesn’t specify how the salt in the battery enables energy storage.