noun
gram equivalent
Technical term in chemistry; the mass of a substance in grams that is chemically equivalent to one gram of hydrogen.
この反応では、酸のグラム当量を計算する必要がある。
In this reaction, you need to calculate the gram equivalent of the acid.
当量 is the general term for 'equivalent' in chemistry, while グラム当量 specifically refers to the gram equivalent.
Compound of グラム (gram) and 当量 (equivalent), a direct calque of the English term 'gram equivalent'.