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AH = +572 kJ for the decomposition of water by the reaction 2H20(1) -2H2(g) + O2(g). How many grams of water can be decomposed by 5.00 x

103 kJ of energy?
O 315 g
O 0.0629 g
O 158 g
O 1.57 x 107 g
O 2.58 x 107 g​

1 Answer

3 votes

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

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