Answer:
P₂N₂I₄
Explanation:
Firstly, we calculate the empirical formula of the compound. To do this we find the moles of each element. Treat the percentages as masses.
The formula for moles is:
[tex]moles = \frac{mass}{relative \: atomic \: mass}[/tex]
The masses of each element are:
Phosphorus = 10.37g
Nitrogen = 4.689g
Iodine = 84.95g
The relative atomic masses of each element are:
Phosphorus = 31.0
Nitrogen = 14.0
Iodine = 126.9
Using these values, we can calculate the moles of each element:
[tex]moles \: of \: phosphorus = \frac{10.37}{31.0} = 0.335[/tex]
[tex]moles \: of \: nitrogen \: = \: \frac{4.689}{14.0} = 0.335[/tex]
[tex]moles \: of \: iodine \: = \: \frac{84.95}{126.9} = 0.669[/tex]
Using the moles, write them in a ratio to find the ratio of moles:
Phosphorus : nitrogen: iodine
0.335 : 0.335: 0.669
The smallest number here is 0.335, so divide each number by 0.335
0.335÷0.335=1
0.335÷0.335=1
0.669÷0.335=1.99... = 2 (round to the nearest whole number)
These numbers are used as the subscripts of each element.
This means that the empirical formula is:
PNI₂
To calculate the molecular formula:
[tex]\frac{molar \: mass \: of \: molecular \: formula}{molar \: mass \: of \: empirical \: formula}[/tex]
The molar mass of empirical formula is adding the molar masses of compound PNI2:
31.0 + 14.0 + 126.9 = 171.9
The molar mass of molecular weight or mass = 298.8 (given from the question)
Substitute these in the formula above:
[tex] \frac{298.8}{171.9} = 1.738...[/tex]
1.738 = 2 rounded to the nearest whole number.
Multiply all the subscripts seen in the empirical formula by the number 2:
PNI₂ × 2 = P₂N₂I₄
