That is because Alchemy is not based on real research and facts, but rather on magic and occultism. Sure, many things in it have been used as basics for some chemistry, but most is false and incorrect.
The answer is chloroplast
When we convert the given mass in grams and volume in liters to m/v percent, we recall that m/v percent is expressed as grams/100 milliliters. In this case the expression becomes (50 grams/ 2500 L)*(0.1L/100ml), that is equal to 0.002 grams/ 100 mL. Hence the the concentration is equal to 0.2 m/v percent.
A) Fe⁰ ----> Fe⁺³ +3e⁻ oxidation | *2
b) <u>Cu⁺² + 2e⁻ -----> Cu⁰ reduction |*3</u>
c) 2Fe⁰ +3Cu⁺² -----> 2Fe⁺³ + 2Cu⁰
