Question

The decomposition of water into hydrogen gas H2 and oxygen gas O2 can be modeled by the balanced chemical equation

A) H2 + O2 → H2O
B) H2O → H2 + O2
C) 2H2 + O2 → 2H2O
D) 2H2O → 2H2 + O2

Answer 1

Answer: D

Explanation: 2H2O → 2H2 + O2 is the correct equation. The equation needs coefficients and water must be the reactant.

Answer 2

D) 2H₂O → 2H₂ + O₂

Step-by-step explanation:

Decomposition means water molecules break up into hydrogen and oxygen molecules.

H₂O → H₂ + O₂

We need to balance the equation. There's one O atom on the left, and two O atoms on the right. Put a 2 in front of H₂O.

2H₂O → H₂ + O₂

Now there's 4 H atoms on the left, and 2 H atoms on the right. Put a 2 in front of H₂.

2H₂O → 2H₂ + O₂

The equation is balanced. There are 4 H atoms and 2 O atoms on either side.