To calculate the amount of water needed to heat 1000 MW/J from 18°C to 30°C, it's essential to clarify the units involved, as MW (megawatts) represents power while Joules represent energy. The specific heat of water is 4.184 J/g·K, which is crucial for the calculation. The discussion highlights confusion regarding the conversion between power and energy, emphasizing the need for a clear understanding of specific heat and its application in the formula. Ultimately, the correct approach involves using the specific heat formula to determine the mass of water required for the specified temperature change. Accurate calculations depend on correctly interpreting the units and applying the specific heat concept.