The study of Alchemy was a precursor for the study of Chemistry.
There was a time when the church had books control. Knowledge was not common. Alchemy was beginning of chemistry we have today. Because of the control of the church, there was a law concerning the contents of manuscripts. Early alchemists hid their work because the punishment was heavy.
Alchemists believed lead to be the oldest metal. It was associated with the planet Saturn. Lead was once refered to as "salt of Saturn" by alchemists and early chemists
The goal was more psychological than spiritual. The alchemists were attempting to cure the "darkness of midlife". The psychologist Carl Jung studied the work of the alchemists for decades, and believed that hidden within their writings, were psychological explanations for their work.
The ability to not understand that alchemy doesn't work.
Perhaps the early Alchemists, although what they were trying to achieve was impossible for the time, they were entrepreneurs.
yes there are some recent alcemists they work for NASA
Cerium was not known by alchemists.
to find a way to avoid death and a way to turn regular items such as coal or stone into gold.
One was to find the "philosopher's stone" a device that could turn lead (a base metal) into gold.
Because the secret is that alchemy doesn't work.
The alchemists were unaware that atoms even existed.
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.