A compound is 42% sodium, 19% phosphorus, and 39% oxygen by mass. What is the empirical formula of this compound? Na3PO4 NaPO Na9P4O8 Na4P3O

Take the one with the smallest percentage, 19% phosphorus and and divide all the other percentages by this number.

**Round to nearest 0.0, 0.25, 0.5, 0.75

P = 19/19 = 1 - - - > 1

O = 39/19 = 2.05 - - > 2

Na = 42/19 = 2.21 - - > 2.25

0.25 = 1/4 So Multiply by 4 to get all ratios to integer values

P = 1*4 = 4

O = 2*4 = 8

Na = 2.25*4 = 9

Answer → Na9P4O8