Misconception 1: "The catalyst increases the yield of ammonia"
The iron catalyst speeds up the rate at which equilibrium is reached — it does NOT change the position of equilibrium or the yield. It allows the process to reach equilibrium faster at a lower temperature.
Misconception 2: "Higher pressure always gives a higher yield, so the highest possible pressure is used"
Higher pressure does increase the yield, but very high pressures are extremely expensive to maintain (strong, thick-walled vessels and powerful compressors) and pose significant safety risks. 200 atm is the economically optimal compromise.
Misconception 3: "Hydrogen comes from the air"
Nitrogen comes from air. Hydrogen is obtained from natural gas (methane reacted with steam in steam reforming).
Quick Check: State one use of the ammonia produced by the Haber process.
Ammonia is used to make fertilisers (e.g. ammonium nitrate or NPK fertilisers). It can also be used to manufacture nitric acid.
This common misconceptions covers Common Misconceptions within The Haber Process & Fertilisers for GCSE Chemistry. Revise The Haber Process & Fertilisers in Rates of Reaction for GCSE Chemistry with 6 exam-style questions and 6 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 9 of 13 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for The Haber Process & Fertilisers
In the Haber process, where is the nitrogen obtained from?
State the equation for the Haber process and give the conditions used. Include the catalyst.