Which of the following substances has the most thermal energy and will transfer the most heat to its surroundings?

• A. An ice cube at 0°C
• B. A cup of water at 100°C
• C. A bathtub full of water at 40°C
• D. A pot of water at 80°C

Answer: (C)

Verified step by step guidance

1. Understand that thermal energy depends on three main factors: the temperature of the substance, the amount (mass) of the substance, and the specific heat capacity of the substance. The formula for thermal energy (heat content) is \(Q = m \times c \times T\), where \(m\) is mass, \(c\) is specific heat capacity, and \(T\) is temperature in Celsius or Kelvin relative to a reference point.
2. Compare the given substances by considering both their temperature and their mass. Even if a substance is at a lower temperature, having a much larger mass can result in greater total thermal energy.
3. Recognize that water has a high specific heat capacity, so differences in mass and temperature will significantly affect the total thermal energy stored.
4. Identify that the bathtub full of water at 40°C likely has a much larger mass than the other options (ice cube, cup, pot), which means its total thermal energy can be greater despite the lower temperature compared to 80°C or 100°C water.
5. Conclude that the substance with the greatest product of mass and temperature (considering specific heat capacity is constant for water) will have the most thermal energy and thus transfer the most heat to its surroundings.