Which balanced equation represents a chemical change?
(1) h2o(l) + energy → h2o(g)
(2) 2h2o(l) + energy → 2h2(g) + o2(g)
(3) h2o(l) → h2o(s) + energy
(4) h2o(g) → h2o(l) + energy

The answer is B because energy was added to 2H2O in order to produce a chemical change of 2H2 and 02 seperately.

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