Question

A) an organic compound is found to contain 11.26% C and 88.74%Cl. What is the empirical formula.
B) the compound above is found to have a molar mass of approx 319g/mol. What is the molecular formula?

Answer 1

think of the percentages as grams and convert to moles

Answer 2

Step 1
take percentages as your mass values for each atom they belong to
Step 2
use the formula of mole
mole= mass/Molecular mass
and find mole of each atom
***if the mole of one of the atoms has decimals- multiply by 2,3,4,5 in order till you get a full number (multiply both moles though, the one with decimals and the other one also)
***if one of your moles has decimals that is very close to full number (ex. 2.98) - you can round it off
***in other cases rounding off is not acceptable
so now you got the moles

these moles basically represent number of C and Cl
Ex. if mole for C is 4 and mole for Cl is also 4
your empirical formula will look like this : C4Cl4

Step 3
calculate molecular mass of the empirical formula you got
then divide given molecular mass of the compound in section B or the question BY the molecular mass of the empirical formula

***if the answer is a full number, ex. 2
then multiply empirical formula by 2 = (C4Cl4) * 2 = C8Cl8

***if the answer has decimals - you can round off to the closes value

Answer 3

Can someone please use my numbers for examples I really don't understand @somy @diamondboy

Answer 4

can't do your work instead of you
first step
we just told you to take percentages as masses
molecular masses you know from periodic table
so put them into the formula and get moles for each

Answer 5

follow this: