To balance the chemical equation, we need to ensure that the number of each type of atom is the same on both sides of the equation.
Starting with the unbalanced equation:
CH4(g) + H2O(g) → CO(g) + H2(g)
1. **Count the number of atoms for each element** in the reactants and products:
- Left side (Reactants):
- C: 1 (from CH4)
- H: 4 (from CH4) + 2 (from H2O) = 6
- O: 1 (from H2O)
- Right side (Products):
- C: 1 (from CO)
- H: 2 (from H2)
- O: 1 (from CO)
2. **Balance the hydrogen atoms**. Currently, there are 6 hydrogen atoms on the left and 2 on the right. We can balance this by changing the coefficient of H2 on the right side to 3:
CH4(g) + H2O(g) → CO(g) + 3 H2(g)
3. **Count the atoms again:**
- Left side:
- C: 1
- H: 4 + 2 = 6
- O: 1
- Right side:
- C: 1
- H: 6 (from 3 H2)
- O: 1
4. **The equation is now balanced**, as we have the same number of carbon, hydrogen, and oxygen atoms on both sides:
CH4(g) + H2O(g) → CO(g) + 3 H2(g)
In summary, the balanced chemical equation for the reaction is:
CH4(g) + H2O(g) → CO(g) + 3 H2(g)
This approach guarantees that the law of conservation of mass is maintained, meaning the total mass of the reactants equals the total mass of the products.