The alchemists were the first chemists. But in addition to mixing chemicals, they also believed that magic would help with their experiments and formulas. It didn't. But their experiments led to the development of the science of chemistry.
scientific m athod
Pennsylvania!
The alchemists wanted to transform iron into gold.
Alchemists tried to make GOLD from base metals. Scientists know that theoretically Gold can only be made by altering the number of protons in an atom. Alchemists did NOT know about protons etc., .
Some famous alchemists include Jabir ibn Hayyan, Paracelsus, and Isaac Newton. They were known for their contributions to the field of alchemy and their beliefs in transmuting base metals into gold and creating the elixir of life.
I don't think "alchemists" is the word you meant to use, because your question does not make sense. Alchemists are people who try to magically turn lead into gold, or otherwise magically turn one substance into another.
three scientific contributations
Because the alchemists learned by trial and error they never tried to take their observations and draw conclusions.
Alchemists study and practice Alchemy which is considered a protoscience. While Alchemists are real people with a real purpose, the field they practice has not been proven real, as yet, by scientific protocol. Using a loose definition, you could call chemists modern alchemists. But there were real alchemists who's main goal was to change one substance into another, usually this a cheap metal, like lead, into gold. Though the methods were primitive, the concepts are considered important work towards modern chemistry.
Lead.
was to make sure that anybody can reach their goal.
Christianity