Firstly divide percentages by molar mass of that element
Na
43.4/23=1.9
C
11.3/12.01=0.94
O
45.3/16=2.83
Then divide the result of the first step by the smallest answer
Na
1.9/.94=2
C
.94/.94=1
O
2.83/.94=3
Empirical Formula is Na2CO3
KCl
The empirical formula is the simplest ratio of the elements within a compound. Therefore, it can be used to calculate the percentage of an element within a compound. For example, the empirical formula for sodium chloride is NaCl. From this, we can see that the ratio of sodium ions to chloride ions is 1Na : 1Cl. Therefore, a sodium chloride molecule is composed of 50% sodium and 50% chloride.
H2co3
AgCl
Because unlike the empirical formula, the molecular formula does not have to be the simplest ratio.If by chance you are given the percent composition of the elements in a substance, you could calculate the empirical formula and then the empirical formula's mass. However, the molecular formula equation is molecular formula= (empirical formula)n, where n is the mass of the molecular formula divided by the mass of the empirical formula. You would, therefore, need to know the mass belonging to the molecular formula, which you are not given.
Chi a+
CHI3
Percent composition can be used to calculate the percentage of an element/compound in a mixture. From the percent composition, you can also find the empirical formula. And from the empirical formula you can find the actual molecular weight.
P2o5
Cr3Si2 is the empirical formula for a compound containing chromium and silicon an has 73.52 mass percent chromium.
p2o5
S2o3
KCl
MgO
C4h2s
CaSO4
If it tells you to find the empirical formula when percent composition is given or if the mass of each element is given in a specific compound.