Coperas or Copperas: How To spell?
The word Coperas is misspelled against Copperas, a noun meaning "Green vitriol, or sulphate of iron; a green crystalline substance, of an astringent taste, used in making ink, in dyeing black, as a tonic in medicine, etc. It is made on a large scale by the oxidation of iron pyrites. Called also ferrous sulphate."
Copperas has double "pp" is mispronounced as "p"Remember double 'PP' in between the strings co & eras which should not be misspelled with single 'P'
Wrong Spelling:  co-p-eras  Correct Spelling:  co-pp-eras 
Find more incorrect spellings of Copperas to spell right way.