The Haber Process

Plants and Nitrogen

Plants provide humans with a crucial food source and remove carbon dioxide from the atmosphere (using photosynthesis). In order to grow, plants need to make proteins, and this requires nitrogen.

Plants can't absorb nitrogen gas

Although nitrogen gas is abundant in the atmosphere (there is lots of it), plants cannot use nitrogen in the air.

Plants absorb nitrates

Instead, plants absorb soluble nitrates (nitrogen-containing compounds) from the soil.

Harvesting crops removes nitrogen

Nitrates re-enter the soil when plants die.
But, harvesting crops takes this nitrogen out of the system.
So, farmers should manually add nitrogen back into the soil.

By reacting nitrogen with hydrogen, the Haber process yields ammonia. Nitrogen-based fertilisers can be made from this ammonia. Farmers can then add the fertiliser back into the soil. The steps involved in the Haber process are:

Collect and purify nitrogen and hydrogen gases

Pass over iron catalyst

Nitrogen and hydrogen are passed over an iron catalyst at a temperature of 450°C and a pressure of 200 atm. This results in the production of ammonia gas.
This reaction is reversible, so not all of the ammonia stays as ammonia - some will break back down to give the reactants, nitrogen and hydrogen.

Condensation

The ammonia gas cools down in a condenser. The ammonia is removed from the condenser once it has become a liquid.

Recycling

We can recycle any unused hydrogen and nitrogen back into the process to create more ammonia. This means that waste of valuable reactants can be avoided!

1Atomic Structure

2Chemical Bonding

2.1Chemical Bonds

2.1.1Types of Bonds

2.1.2Ionic Bonds

2.1.3Ionic Compounds

2.1.4Covalent & Metallic Bonds

2.1.5Representing Covalent Bonds

2.1.6Dots-And-Cross Diagrams

2.1.7Exam-Style Questions - Chemical Bonds

2.2States of Matter

2.2.1States of Matter

2.2.2Changing State

2.2.3Changing State HyperLearning

2.2.4State Symbols

2.2.5Exam-Style Questions - States of Matter

2.3Chemical Properties

2.3.1Chemical Properties of Ionic Compounds

2.3.2Chemical Properties of Small Molecules

2.3.3Molecular Forces & Polymers

2.3.4Metals & Giant Covalent Structures

2.3.5Alloys & Conductors

2.3.6Carbon Structures - Diamond & Graphite

2.3.7Carbon Structures - Graphene & Fullerenes

2.3.8Carbon Structures - Summary

2.3.9Nanoparticles

2.3.10Nanotechnology

2.3.11Surface Area to Volume Ratio & Nanotechnology Uses

2.3.12End of Topic Test - Chemical Bonding

2.3.13Grade 9 - Bonding & Structure

2.3.14Exam-Style Questions - Allotropes of Carbon

3Quantitative Chemistry

4Chemical Changes

5Energy Changes

5.1Exothermic & Endothermic Reactions

5.1.1Energy Conservation

5.1.2Exothermic & Endothermic Reactions

5.1.3Reaction Profiles

5.1.4Reaction Profiles 2

5.2Chemical Cells & Fuel Cells

5.2.1Chemical Cells

5.2.2Batteries & Charging of Cells

5.2.3Fuel Cells

5.2.4Hydrogen Fuel Cell

5.2.5End of Topic Test - Energy Changes

5.2.6Grade 9 - Energy Changes

5.2.7Exam-Style Questions - Fuel Cells

6The Rate & Extent of Chemical Change

6.1Rate of Reaction

6.1.1Chemical Reactions

6.1.2Collision Theory

6.1.3Catalysts

6.1.4Catalysts in Industry

6.2Reversible Reactions

6.2.1Reversible Reactions

6.2.2Equilibrium

6.2.3Equilibrium Position

6.2.4Equilibrium Position 2

6.2.5End of Topic Test - Rates of Reaction

6.2.6Grade 9 - Rate & Extent of Chemical Change

6.2.7Exam-Style Questions - Reversible Reactions

7Organic Chemistry

8Chemical Analysis

8.1Purity, Formulations & Chromatography

8.1.1Purity & Formulations

8.1.2Chromatography

8.1.3Paper Chromatography 1

8.1.4Paper Chromatography 2

8.1.5Required Practical - Paper Chromatography

8.2Identification of Common Gases

8.2.1Identification of Hydrogen & Oxygen

8.2.2Identification of Carbon Dioxide & Chlorine

8.3Identifying Ions

8.3.1Flame Tests

8.3.2Required Practical: Flame Tests

8.3.3Metal Hydroxides

8.3.4Carbonates

8.3.5Halides, Sulfates

8.3.6Methodology for Chemical Analysis

8.3.7Flame Emission Spectroscopy

8.3.8End of Topic Test - Chemical Analysis

8.3.9Grade 9 - Chemical Analysis

8.3.10Exam-Style Questions - Identification of ions

9Chemistry of the Atmosphere

9.1The Earth's Atmosphere

9.1.1Proportions of Gases in the Atmosphere

9.1.2Oxygen & Carbon Dioxide in the Atmosphere

9.1.3Greenhouse Gases & Human Activities

9.1.4Greenhouse Gases & Human Activities

9.1.5Greenhouse Gases & Climate Change

9.1.6Carbon Footprints

9.1.7Common Atmospheric Pollutants & Their Properties

9.1.8End of Topic Test - The Earth

9.1.9Grade 9 - Chemistry of the Atmosphere

9.1.10Exam-Style Questions - Earth's Atmosphere

10Using Resources

10.1Using the Earth's Resources

10.1.1Potable Water & its Sources

10.1.2Potable Water in the UK & in Saudi Arabia

10.1.3Natural Resources

10.1.4Waste Water

10.1.5Metal Ore Extraction & the Properties of Copper

10.1.6Overexploitation & Alternative Extraction Methods

10.2Life Cycle Assessments & Recycling

10.2.1Life Cycle Assessments

10.2.2Difficulties with LCA

10.2.3Reducing Resource Usage

10.2.4Reducing Use of Metal and Glass

10.2.5Exam-Style Questions - Life Cycle Assessments

10.3Using Materials

10.3.1Corrosion

10.3.2Alloys

10.3.3Ceramics

10.3.4Polymers & Composites

10.4The Haber Process & NPK Fertilisers

10.4.1The Haber Process

10.4.2The Haber Process - Equation & Trade-Offs

10.4.3Formulated vs Manure Fertilisers

10.4.4NPK Fertilisers 1

10.4.5NPK Fertilisers 2

10.4.6End of Topic Test - Resources

10.4.7Grade 9 - Using Resources

10.4.8Exam-Style Questions - The Haber Process

Jump to other topics