Final answer:
To find the empirical formula of a compound with given percentages, we convert the percentages to grams, divide the grams by the atomic masses to find the mole ratios, and round the mole ratios to the nearest whole number.
Step-by-step explanation:
To determine the empirical formula of a compound, we need to find the smallest whole number ratio of the elements present in the compound. To do this, we can assume we have 100g of the compound and convert the percentage composition to grams. Then we can find the molar mass of each element by dividing the mass in grams by its atomic mass.
Next, we divide the molar masses by the smallest molar mass to find the mole ratios. Finally, we round the mole ratios to the nearest whole number to get the empirical formula.
In this case, we have 15.12g of phosphorus, 6.841g of nitrogen, and 78.03g of bromine. The molar masses of phosphorus, nitrogen, and bromine are 31g/mol, 14g/mol, and 80g/mol, respectively. Dividing the molar masses by their smallest value of 14g/mol, we get a mole ratio of approximately 2.214:1.043:5.714. Rounding to the nearest whole number, we have a final empirical formula of P2N1Br6.