Dưới đây là các phương trình hóa học cho sơ đồ chuyển hóa bạn đã cung cấp:

### a.
1. \( \text{C} + \text{O}_2 \rightarrow \text{CO}_2 \) (1)
2. \( \text{CO}_2 + \text{CaO} \rightarrow \text{CaCO}_3 \) (2)
3. \( \text{CaCO}_3 \xrightarrow{t^o} \text{Ca(HCO}_3)_2 \) (3)
4. \( \text{Ca(HCO}_3)_2 \rightarrow \text{CaCO}_3 + \text{CO}_2 + \text{H}_2\text{O} \) (4)
5. \( \text{C} + \text{O}_2 \rightarrow \text{CO} \) (5)
6. \( \text{CO} + \text{O}_2 \rightarrow \text{CO}_2 \) (6)

### b.
1. \( \text{C} + \text{O}_2 \rightarrow \text{CO}_2 \) (1)
2. \( \text{CO}_2 + \text{Na}_2\text{CO}_3 \rightarrow \text{BaCO}_3 \) (2)
3. \( \text{BaCO}_3 \xrightarrow{t^o} \text{Ba(HCO}_3)_2 \) (3)
4. \( \text{Ba(HCO}_3)_2 \rightarrow \text{BaCO}_3 + \text{CO}_2 + \text{H}_2\text{O} \) (4)
5. \( \text{BaCO}_3 \rightarrow \text{Ba(NO}_3)_2 \) (5)
6. \( \text{Ba(NO}_3)_2 \rightarrow \text{BaO} + \text{2NO}_2 + \text{1/2O}_2 \) (6)
7. \( \text{BaO} + \text{HNO}_3 \rightarrow \text{Ba(NO}_3)_2 + \text{H}_2\text{O} \) (7)
8. \( \text{Ba(NO}_3)_2 + 6\text{HNO}_3 \rightarrow \text{Fe(NO}_3)_3 + 6\text{H}_2\text{O} \) (8)
9. \( \text{Fe}_2\text{O}_3 + 6\text{H}_2\text{O} \rightarrow 2\text{Fe(NO}_3)_3 + 6\text{HNO}_3 \) (9)
10. \( \text{Fe(NO}_3)_3 \rightarrow \text{Fe}_2\text{O}_3 + 3\text{N}_2 + 6\text{O}_2 \) (10)

Hy vọng điều này giúp ích cho bạn!