Which has a greater heat capacity: iron or water?

• A. Water
• B. Iron

Answer: (A)

Verified step by step guidance

1. Understand the concept of heat capacity: Heat capacity is the amount of heat required to raise the temperature of a substance by 1 degree Celsius (or 1 Kelvin). It depends on both the amount of substance and the type of material.
2. Recognize the difference between heat capacity and specific heat capacity: Heat capacity is an extensive property (depends on the amount of substance), while specific heat capacity is an intensive property (heat capacity per unit mass). Here, the question is about the general heat capacity of iron versus water, which usually implies comparing their specific heat capacities for the same amount.
3. Recall the specific heat capacities of iron and water: Water has a high specific heat capacity (about 4.18 J/g°C), meaning it requires more heat to raise its temperature compared to iron, which has a lower specific heat capacity (about 0.45 J/g°C).
4. Compare the values: Since water's specific heat capacity is significantly higher than that of iron, for the same mass, water will absorb more heat to increase its temperature by 1°C, indicating a greater heat capacity.
5. Conclude that water has a greater heat capacity than iron because it can store more heat energy per gram per degree Celsius increase in temperature.