Posted by Coco on .
An acid is comprised of 0.2g hydrogen, 7.1g chlorine and 12.8g oxygen. What is the most likely formula for this acid.

Chemistry 
DrBob222,
Convert g to moles and find the ratio, in whole numbers. The easiest way to do that is to divide the smallest number by itself, then divide all the other molar quantities by that same small number. Post your work if you get stuck.

Chemistry 
Coco,
im not getting an answer

Chemistry 
DrBob222,
moles H = 0.2/1 = 0.2
moles Cl = 7.1/35.457 = 0.2
moles O = 12.8/16 = 0.8
So the empirical formula is
H_{0.2}Cl_{0.2}O_{0.8} BUT formulas are denoted with small whole numbers for the subscripts. So change all of them to make them into whole numbers AND keep the ratio the same. I repeat, the easiest way to do this is to divide the smallest number by itself, then divide the other two numbers by the same small number. You should come out with 3 small whole numbers.