Question

25. Balance the following the chemical equation: C2H6 + O2 → CO2 + H2O

Answer 1

To balance the chemical equation \( C_2H_6 + O_2 \rightarrow CO_2 + H_2O \), we will follow these steps:

1. **Count the number of atoms of each element on both sides of the equation:**
- On the left side:
- Carbon (C): 2 (from C2H6)
- Hydrogen (H): 6 (from C2H6)
- Oxygen (O): 2 (from O2)

- On the right side:
- Carbon (C): 1 (from CO2)
- Hydrogen (H): 2 (from H2O)
- Oxygen (O): 3 (1 from CO2 and 1 from H2O)

2. **Start balancing with carbon (C):**
- There are 2 carbons on the left, so we need 2 CO2 on the right.
\[
C_2H_6 + O_2 \rightarrow 2CO_2 + H_2O
\]

3. **Now the equation looks like this:**
- On the right side now we have:
- C: 2
- H: 6 (still needs balancing)
- O: 4 (from 2 CO2) + 1 (from H2O) = 5

4. **Next balance the hydrogen (H):**
- There are 6 hydrogens in C2H6, so we need 3 H2O on the right.
\[
C_2H_6 + O_2 \rightarrow 2CO_2 + 3H_2O
\]

5. **Now count the atoms again:**
- Right side:
- C: 2 (from 2CO2)
- H: 6 (from 3H2O)
- O: 4 (from 2CO2) + 3 (from 3H2O) = 7

6. **Now balance the oxygen (O):**
- We have 7 oxygen atoms on the right side. In O2, each molecule contains 2 oxygen atoms, so we need:
\[
\frac{7}{2} \text{ O}_2 = 3.5 \text{ O}_2
\]
But it’s not preferred to have a fraction in a balanced equation, so we multiply everything by 2 to eliminate the fraction:
\[
2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O
\]

7. **Final balanced equation:**
\[
\boxed{2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O}
\]

This balanced equation has equal numbers of each type of atom on both sides.