How much energy is released when 42.5 g of water freezes at 0°C? (The enthalpy of fusion for water is 334 J/g.)

• A. 334 J
• B. 14,200 J
• C. 142,000 J
• D. 1,420 J

Answer: (B)

Verified step by step guidance

1. Identify the given information: mass of water (m) = 42.5 g, enthalpy of fusion (\( \Delta H_{fusion} \)) = 334 J/g. Since freezing is the reverse of fusion, the energy released will be the same magnitude but released (exothermic process).
2. Understand that the energy released when water freezes can be calculated by multiplying the mass of the water by the enthalpy of fusion per gram: \( q = m \times \Delta H_{fusion} \).
3. Set up the equation for the energy released: \( q = 42.5\, \text{g} \times 334\, \text{J/g} \).
4. Calculate the product to find the total energy released during freezing. This value will be positive, indicating energy released to the surroundings.
5. Express the final answer with appropriate units (Joules) and consider significant figures based on the given data.