Which of the following substances would retain the most heat for the longest period of time, assuming equal masses and identical heating conditions?

• A. Copper (specific heat capacity = 0.39 J/g·K)
• B. Water (specific heat capacity = 4.18 J/g·K)
• C. Ethanol (specific heat capacity = 2.44 J/g·K)
• D. Iron (specific heat capacity = 0.45 J/g·K)

Answer: (B)

Verified step by step guidance

1. Understand that the ability of a substance to retain heat is related to its specific heat capacity, which is the amount of heat required to raise the temperature of 1 gram of the substance by 1 Kelvin (or degree Celsius).
2. Recall that a higher specific heat capacity means the substance can absorb more heat without a large change in temperature, thus it retains heat longer.
3. Compare the given specific heat capacities: Copper (0.39 J/g\cdot K), Water (4.18 J/g\cdot K), Ethanol (2.44 J/g\cdot K), and Iron (0.45 J/g\cdot K).
4. Since all substances have equal masses and are subjected to identical heating conditions, the substance with the highest specific heat capacity will retain the most heat for the longest time.
5. Conclude that water, having the highest specific heat capacity among the options, will retain heat the longest under the given conditions.