What is stoichiometry?
See this old answer and links. All chemical reactions observe
The balancing of chemical equations follows conservation of mass. If there are
In the case of multi-step syntheses (and some chemists specialize in the reactions), even a four step sequence with 90% yield at each step (and a synthetic chemist would gladly accept a 90% yield), the overall yield is reduced to 66% automatically. And this reflects mass equivalence: