Which action would involve the greatest transfer of heat?

• A. Changing the temperature of 1 g of water from 10°C to 90°C
• B. Cooling 10 g of water from 80°C to 40°C
• C. Evaporating 1 g of water at 25°C
• D. Condensing 5 g of steam to liquid water

Answer: (D)

Verified step by step guidance

1. Understand that heat transfer involves either changing the temperature of a substance or changing its state (phase change).
2. Identify the specific heat capacity of water, which is approximately 4.18 J/g°C, to calculate the heat required for temperature changes.
3. For temperature changes, use the formula: $q=mc\Delta T$, where $q$ is the heat transferred, $m$ is the mass, $c$ is the specific heat capacity, and $\mathrm{\Delta T}$ is the change in temperature.
4. For phase changes, use the latent heat of vaporization or condensation. The latent heat of vaporization for water is approximately 2260 J/g, which is the same for condensation.
5. Calculate the heat transfer for each scenario: temperature changes involve multiplying mass, specific heat, and temperature change; phase changes involve multiplying mass by latent heat. Compare these values to determine which action involves the greatest transfer of heat.