What 4 elements did people originally think made up everything?

Amonoprotic acid is an acid that donates a single proton to the solution. suppose you have 0.140 g of a monoprotic acid dissolved in 35.0 ml of water. this solution is then neutralized with 14.5 ml of 0.110 m naoh. what is the molar mass of the acid?

Two things that biomedical has invented or innovated

Element before carbon on the periodic table