Methane (CH4) and oxygen (O2) combine to make carbon dioxide (CO2) and water (H2O) in the following unbalanced equation. CH4 + O2 → CO2 + H2O How many oxygen molecules are necessary in order to complete this reaction? (1 point) Responses one one three three four four two two

Answer 1

To balance the reaction between methane (CH4) and oxygen (O2) that forms carbon dioxide (CO2) and water (H2O), we can follow these steps:

1. Write the unbalanced equation: \[ \text{CH}_4 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \]

2. Count the number of each type of atom on both sides of the equation:

   • Left side: 1 C (from CH4), 4 H (from CH4), 2 O (from O2)
   • Right side: 1 C (from CO2), 2 H (from H2O), 3 O (1 from CO2 and 2 from H2O)

3. To balance the equation, we'll start with carbon and hydrogen:

   • Carbon: 1 on both sides (already balanced).
   • For hydrogen, we need 4 H on the right side, so we need to have 2 H2O molecules: \[ \text{CH}_4 + \text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \]

4. Now, the equation looks like: \[ \text{CH}_4 + \text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \] At this point, there are:

   • Left side: 1 C, 4 H (from CH4), 2 O
   • Right side: 1 C, 4 H (from 2 H2O), and 3 O (1 from CO2 and 2 from 2 H2O)

5. To balance the oxygen, you have 2 O on the left and 3 O on the right. To balance the oxygen, you need 2 O2 molecules: \[ \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \]

6. Now we can check the count again:

   • Left: 1 C, 4 H (from CH4), 4 O (from 2 O2)
   • Right: 1 C, 4 H (from 2 H2O), 4 O (3 from products)

After balancing, the final balanced equation is: \[ \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \]

Conclusion: Two O2 molecules are necessary to complete the reaction. The correct response is two.