Question

Balance the following chemical equation and classify them into their different classes;
d) C2H6 + O2 produce CO2 + H2O
e) NO+ O2 produce NO2

Answer 1

To balance the given chemical equations and classify them, let's work through each equation step-by-step.

### d) C2H6 + O2 → CO2 + H2O

**Balancing the equation:**

1. **Count the number of each type of atom on both sides:**
- Reactants: C (2), H (6), O (2)
- Products: C (1 for CO2), H (2 for H2O), O (3 total: 2 for CO2 + 1 for H2O)

2. **Balance carbon (C):**
- Place a coefficient of 2 in front of CO2:
\[
C2H6 + O2 → 2CO2 + H2O
\]

3. **Balance hydrogen (H):**
- Place a coefficient of 3 in front of H2O:
\[
C2H6 + O2 → 2CO2 + 3H2O
\]

4. **Balance oxygen (O):**
- Now we have 4 O (from 2 CO2) + 3 O (from 3 H2O) = 7 O total on the products side.
- To get 7 O from O2 (which gives 2 O per molecule), we need \( \frac{7}{2} \) or 3.5 O2. To eliminate the fraction, we can multiply the entire equation by 2:
\[
2C2H6 + 7O2 → 4CO2 + 6H2O
\]

**Final balanced equation:**
\[
2C2H6 + 7O2 → 4CO2 + 6H2O
\]

**Classification:**
- This reaction is a **combustion reaction** since it involves the burning of an alkane (C2H6) in the presence of oxygen.

---

### e) NO + O2 → NO2

**Balancing the equation:**

1. **Count the number of each type of atom on both sides:**
- Reactants: N (1 for NO), O (2)
- Products: N (1 for NO2), O (2 total: 1 from NO2 for 1 N and 1 from O2)

2. **Since nitrogen (N) and oxygen (O) are already balanced, we can write:**
\[
NO + O2 → NO2
\]

**Final balanced equation:**
\[
2NO + O2 → 2NO2
\]

**Classification:**
- This reaction is an **oxidation-reduction (redox) reaction** as nitrogen monoxide (NO) is oxidized to nitrogen dioxide (NO2) in the presence of oxygen.

### Summary:
- **d)** 2C2H6 + 7O2 → 4CO2 + 6H2O - Combustion reaction
- **e)** 2NO + O2 → 2NO2 - Oxidation-reduction (redox) reaction