Here we have to get the amount of heat will generate by 510.0 kg of sodium sulfate decahydrate at night assuming complete reaction and 100% efficiency of heat transfer.
510.0 kg of sodium sulfate decahydrate will produce 5.603 × 10⁵ kJ of heat energy.
The molecular weight of sodium sulfate decahydrate (H₂₀Na₂O₁₄S) 322.186 g/mol.
Thus 510.0 kg of H₂₀Na₂O₁₄S is equivalent to [tex]\frac{510000g}{322.186g/mol}[/tex] = 1582.936 mol of H₂₀Na₂O₁₄S.
Now per mole of H₂₀Na₂O₁₄S will transfer 354 kJ heat.
Thus 1582.936 mol will transfer 1582.936 × 354 kJ = 5.603×10⁵ kJ of heat.
Henceforth, 510.0 kg of sodium sulfate decahydrate will produce 5.603 × 10⁵ kJ of heat energy.