# Iron and its oxides: reaction diagrams

> Reagent and condition for every arrow


## Objectives

- Choose the reagent and condition for each arrow in a diagram of iron and its oxides.
- Write the balanced equation for each step.

## 1. Iron oxides




## 2. Same reactants, different products

Predict: can CO and $\ce{Fe2O3}$ give different products?

- Yes: the temperature decides the product. ✓
- No: the same reactants always give the same product.

CO and $\ce{Fe2O3}$ can give different products: the temperature decides. At 230–300 °C they give $\ce{Fe3O4}$, and above 700 °C they give iron, so the condition over the arrow is part of the reaction.

[ar-EG] الـ CO والـ $\ce{Fe2O3}$ ممكن يدّوا نواتج مختلفة، ودرجة الحرارة هي اللي بتحدد: عند 230–300 °C بيدّوا $\ce{Fe3O4}$، وعند أعلى من 700 °C بيدّوا iron، يعني الظرف اللي فوق السهم جزء من الـ reaction.
## 3. Read each arrow: up or down?

Up adds oxygen: oxidation, by air or $\ce{O2}$ with heat. Down removes oxygen: reduction, by $\ce{H2}$ or CO. Then pick the exact condition. It decides the product. The condition over the arrow does not change the product.


## 4. Worked: diagram (a)

Book Q6 (a) 1. Fe → Fe₃O₄ Up: red hot iron in dry air or oxygen. 2. Fe₃O₄ → FeO Down, middle rung: hydrogen at 400–700 °C. 3. FeO → Fe₂O₃ Up: FeO is easily oxidized in hot air. 4. Fe₂O₃ → Fe Down all the way: the blast furnace equation.


## 5. Faded: diagram (b)

Book Q6 (b), main path. It also has Fe₃O₄ → Fe₂O₃ and Fe₂O₃ → Fe. The same reagent always gives the same product. Arrow 1, done for you Arrow 2: heat iron (II) sulphate. Arrow 3: the lowest rung.


## 6. Which rung?

$\ce{Fe2O3}$ is reduced under each condition. Sort by the product.


## 7. Your turn: the last arrows

Diagram (b), $\ce{Fe3O4}$ → $\ce{Fe2O3}$: heat in air. Use whole numbers. Which reagent and condition turn $\ce{Fe3O4}$ into iron? Which condition turns FeO into $\ce{Fe2O3}$?


## 8. Summary

Up (more oxygen): air or $\ce{O2}$ with heat. Down (less oxygen): $\ce{H2}$ or CO; the temperature decides how far. $\ce{Fe2O3}$ + CO: 230–300 °C → $\ce{Fe3O4}$; 400–700 °C → FeO; higher than 700 °C → Fe. Fe → $\ce{FeSO4}$: dilute $\ce{H2SO4}$. $\ce{FeSO4}$ → $\ce{Fe2O3}$: heat. Diagram questions (Q6): write each equation with its condition over the arrow. Can you explain why CO gives Fe₃O₄ in one case and iron in another? The temperature decides how much oxygen CO removes. At 230–300 °C, CO turns $\ce{Fe2O3}$ into $\ce{Fe3O4}$; higher than 700 °C, it removes all the oxygen and gives iron.



Chapter: Transition Elements (https://yaani.ai/ar/learn/chemistry/chem-s3-en.ch1)
Source: https://yaani.ai/ar/lesson/chem-s3-en.lesson-fe.conversions