How do you solve empirical formula calculations?

Question

Peyton Adams · Accepted Answer

The explanation is given below.

First, assume that percentages represent the masses that make up a total of 100 grams. Step 2 : Use #n = m /M# formula to calculate the number of moles in each atom. #n# = number of moles #m# = mass of substance #M# = molar mass Step 3: Calculate the smallest mole by dividing the total moles. Step 4: Assign them as subscripts after rounding them to the nearest whole number. Example question: Calculate empirical formula of a compound that has #11%# hydrogen and #89%# oxygen. Assume that 100 grams contains #11# #g# of #H# and #89# #g# of #O#. To move on to step 2, you also need to know the molar mass of #H# and #O#. In that case, the molar mass of #H# is #1.0# #g#/#mol# and the molar mass of #O# is #16.0# #g#/#mol#. Now you can find the number of moles for each atom. #n(H)# = #11/1.0# = #11# moles #n (O)# = #89/16.0# = #5.6# moles Step 3, multiply the number of moles by the smallest. #H# = #11 / 5.6 = 2.00# #O = 5.6 /5.6= 1.00# *Has been rounded to nearest whole number Step 4, assign them as subscripts. Since there is 2 Hydrogen and and 1 Oxygen, you know that the empirical formula is #H_2O#.

Wyatt Adkins · Answer

undefined The steps involved in solving the empirical formula calculations are as follows: 1. Find the mass of each element in the compound; 2. Use the element's molar mass to convert the mass of each element to a mole; 3. Divide the total number of moles by the lowest number of moles calculated; and, if required, multiply the resultant numbers to get whole numbers, which stand in for the subscripts in the empirical formula.