A chemical analysis of an inorganic compound shows that it contains 40 % of element P , 30 % of element Q , and 30 % of element R by mass. If the respective atomic masses of P, Q , and R are 40 u , 60 u , and 20 u , the empirical formula of the compound is:

Step-by-step solution

Moles of element P = 40 40 = 1 Moles of element Q = 30 60 = 0.5 Moles of element R = 30 20 = 1.5 The molar ratio of P : Q : R is 1 : 0.5 : 1.5 To obtain the simplest whole number ratio, divide by the smallest value ( 0.5 ): P : Q : R = 1 0.5 : 0.5 0.5 : 1.5 0.5 = 2 : 1 : 3 The empirical formula of the compound is P ₂ QR ₃ . Answer: P ₂ QR ₃