Multiply the total number of atoms inside the parentheses by the Totaling Atoms Using PSEC Parentheses Count up the total number of atoms inside the parentheses Subscripts Multiply the total number of atoms inside the parentheses by the subscript value Extras Add any extra atoms that were not yet accounted for to the total Coefficients Multiply the total number of atoms (from PSE) by the coefficient

Examples Parentheses Subscripts Extras Coefficients 2Ba(NO3)2 4(NH4)3PO4 P – 4 atoms total N 1 O 3 4 atoms Parentheses P – 5 atoms total N 1 H 4 5 atoms Subscripts S – 8 atoms total (4)(2) = 8 atoms S – 15 atoms total (5)(3) = 15 atoms Extras E – 9 atoms total 8 + 1 = 9 atoms E – 20 atoms total 15 + 5 = 20 atoms C – 18 atoms total (9)(2) = 18 atoms Coefficients C – 80 atoms total (20)(4) = 80 atoms