草酸 (cǎosuān): oxalic acid (H2C2O4)

Meanings

Bōcài hányǒu jiào duō de cǎosuān.

Spinach contains a relatively high amount of oxalic acid.

Cǎosuān kěyǐ yònglái qùchú tiěxiù.

Oxalic acid can be used to remove rust.

memory

Literally 草 (grass / plant) + 酸 (acid) — oxalic acid was first isolated from wood sorrel (Oxalis), hence the name in both Chinese and Latin.

草 cǎo

酸 suān