Calculate the percentage composition by mass of Lithium Sulfate, Li2SO4.

(Taken from GCSE WJEC Additional Science Book- First Published in 2012) and I have adapted the answer given.Relative atomic masses: Li = 7 ; S= 32 ; O=161) Calculate molecular mass of lithium sulfate (Li2SO4)= 2(Li) + 1(S) + 4 (O) = 2(7) + 1(32) + 4(16) = 1102) Working out % composition of each element (think of it as a working it out like you do your test percentages, where the atomic mass of element is your test score, and the molecular mass of compound is the total :) )% composition of Li = (2(Li)/ Li2SO4) x 100 = (2(7)/ 110) x 100 = (14/110) x 100 = 12.7%
% composition of S = (1(S)/ Li2SO4) x 100 = (1(32)/ 110) x 100 = (32/110 x 100) = 29.1%
% composition of O = (4(O)/ Li2SO4) x 100 = (4 (16)/ 110 ) x 100 = (64/110) x 100 = 58.2%