The equation for water is H2 +O2 → H2O. To balance the equation, which coefficient should be placed in front of H2 and H2O?

Question

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Answer 1

To balance the equation for the formation of water (H2O) from hydrogen (H2) and oxygen (O2), we start with the unbalanced equation:

\[ \text{H}_2 + \text{O}_2 \rightarrow \text{H}_2\text{O} \]

1. Count the number of atoms on each side:

   • Reactants:
     • H: 2 (from H2)
     • O: 2 (from O2)
   • Products:
     • H: 2 (from H2O)
     • O: 1 (from H2O)

2. Balancing the equation:

   • The number of hydrogen atoms is already balanced, but the oxygen atoms are not. To balance the oxygen (O), we need 2 oxygen atoms in the products.
   • Since each water molecule (H2O) contains 1 oxygen atom, we need 2 water molecules to have 2 oxygen atoms:

\[ \text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} \]

3. Adjusting the hydrogen coefficient:
   • Now, with 2 molecules of water, we have 4 hydrogen atoms (2 x H2O) on the right side, so we need to place a coefficient of 2 in front of H2 to balance the hydrogen:

\[ 2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} \]

Now the equation is fully balanced.

Final balanced equation:

\[ 2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} \]

Coefficients placed:

• Place 2 in front of H2 and H2O.

So, the answer is 2.