Calculate the empirical formula of a compound having percentage composition:
Potassium (K) = 26.57, Chromium (Cr) = 35.36, Oxygen (O) = 38.07.
(Given the Atomic weights of K, Cr and O are 39, 52 and 16 respectively)

Calculate the empirical formula of a compound having following - percentage composition. Carbon = 25.41%, hydrogen 3.17%, oxygen = 33.86% and chlorine 37.56%.[C = 12 , H = 1 , O = 16 , Cl = 35.5)

Calculate the empirical and molecular formula of the compound having the following percentage composition : Na = 36.5%, H = 0.8%, P = 24.6%, O = 38.1% The molecular mass of the compound is 126 a.m.u. Also name the compound

Calculate the empirical formula of the compound having 37.6% sodium 23.1 % silicon and 39.3% oxygen (workout to two decimal places). (O = 16, Na= 23, Si= 28)

Determine the empirical formula of the compound whose composition by mass is : 42% nitrogen, 48% oxygen and 9% hydrogen. (H = 1, N = 14, O = 16)

Calculate the oxidation number of chromium in K_2Cr_2O_7 .