Why do you think properties of materials used would be considered a constraint?

For a material to be considered as building material, it should have required engineering properties suitable for construction works. These properties of building materials are responsible for its quality and capacity and helps to decide applications of these material. Such properties of building materials are categorized as follows. 1. Physical properties 2. Mechanical properties 3. Chemical properties 4. Electrical properties 5. Magnetic properties 6. Thermal properties

Explanation:

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .