Question

Balance the following reaction (4 points): CH4 + O2 → CO2 + H2O

Answer 1

To balance the chemical reaction \( \text{CH}_4 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \), follow these steps:

1. **List the number of atoms of each element** on both sides:
- Reactants:
- C: 1 (from \( \text{CH}_4 \))
- H: 4 (from \( \text{CH}_4 \))
- O: 2 (from \( \text{O}_2 \))

- Products:
- C: 1 (from \( \text{CO}_2 \))
- H: 2 (from \( \text{H}_2\text{O} \))
- O: 3 (2 from \( \text{CO}_2 \) and 1 from \( \text{H}_2\text{O} \))

2. **Balance the hydrogen atoms** by putting a coefficient of **2** in front of \( \text{H}_2\text{O} \):
\[
\text{CH}_4 + \text{O}_2 \rightarrow \text{CO}_2 + 2 \text{H}_2\text{O}
\]

3. **Now count the atoms again**:
- Reactants:
- C: 1
- H: 4
- O: 2
- Products:
- C: 1
- H: 4 (because \( 2 \times 2 = 4 \))
- O: 2 + 2 = 4 (2 from \( \text{CO}_2 \) and 2 from \( 2 \text{H}_2\text{O} \))

4. **Balance the oxygen** by adjusting the coefficient of \( \text{O}_2 \) to **2**:
\[
\text{CH}_4 + 2 \text{O}_2 \rightarrow \text{CO}_2 + 2 \text{H}_2\text{O}
\]

5. **Final count**:
- Reactants:
- C: 1
- H: 4
- O: 4 (from \( 2 \text{O}_2 \))
- Products:
- C: 1
- H: 4
- O: 4 (2 from \( \text{CO}_2 \) and 2 from \( 2 \text{H}_2\text{O} \))

Now both sides of the equation are balanced.

The balanced equation is:
\[
\text{CH}_4 + 2 \text{O}_2 \rightarrow \text{CO}_2 + 2 \text{H}_2\text{O}
\]