Determine the empirical formula of each of the following compounds. (Type your answer using the format CH4 for CH4 and list the elements in the same order as they are mentioned in the problem.)
(a) 0.063 mol chlorine atoms combined with 0.22 mol oxygen atoms
(b) 3.27 g silicon combined with 12.4 g chlorine
(c) 42.9 mass % carbon and 57.1 mass % oxygen