Answer:
315 g
Step-by-step explanation:
We must return to the reaction equation as a guide in solving the problem;
2H20(1) ------------> 2H2(g) + O2(g).
We can see from the equation that the decomposition of 2 moles of water released 572 KJ of energy
Therefore, x moles of water will release 5.0 ×10^3 KJ of energy
x= 5.0×10^3 × 2/572
x= 17.48 moles of water
Mass of water = number of moles × molar mass
Molar mass of water = 18gmol-1
Mass of water = 17.48 × 18
Mass of water= 315 g