In the balanced reaction that makes ammonia, how many moles of hydrogen react with one mole of nitrogen?

1. The number written in front of a substance in a balanced equation gives the mole ratio. 2. If no number is written, that number is taken to be one. 3. For the synthesis of ammonia the balanced equation carries a one, a three and a two. 4. One mole of nitrogen molecules reacts with three moles of hydrogen molecules. 5. Those two together produce two moles of ammonia molecules. 6. So three moles of hydrogen are needed for every one mole of nitrogen. 7. Answering two picks up the ammonia coefficient by mistake rather than the hydrogen one. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 19: Quantitative aspects of chemical change_