Question

Getting empirical formula, but they also gave molar mass too.

Answer 1

Answer:

Empirical formula is PNCl₂

Explanation:

Percent composition means that 100 g of compound has x g of each element.

In 100 g of compound x, we have 26.73 g of P, 12.09 g of N, 61.18 g of Cl.

So, let's make some rules of three:

In 100 g of compound we have 26.73 g of P, 12.09 g of N, 61.18 g of Cl

In 579.43 g of compound we have:

(579.43 . 26.73) / 100 = 155 g of P

(579.43 . 12.09) / 100 = 70 g of N

(579.43 . 61.18) / 100 = 354 g of Cl

Let's convert the mass of the elements in moles.

155 g of P / 30.97 g/mol = 5 P

70 g / 14 g/mol = 5 N

354 g / 35.45 g/mol = 10 Cl

Answer 2

Answer:

The empirical formula has a molar mass of 115.88 g/mol

The molecular formula = P5N5Cl10

Explanation:

Step 1: Data given

Suppose the mass of compound X = 100.0 grams

Compound X contains:

26.73 % phosphorus = 26.73 grams

12.09 % nitrogen = 12.09 grams

61.18 % chlorine = 61.18 grams

Molar mass of phosphorus = 30.97 g/mol

Molar mass of nitrogen = 14.01 g/mol

Molar mass of chlorine = 35.45 g/mol

Step 2: Calculate moles

Mol = mass / molar mass

Mol P = 26.73 grams / 30.97 g/mol

Mol P = 0.8631 moles

Mol N = 12.09 grams / 14.01 g/mol

Mol N = 0.8630 moles

Mol Cl = 61.18 grams / 35.45 g/mol

Mol Cl = 1.726 moles

Step 3: Calculate mol ratio

We divide by the smallest amount of moles

P: 0.8631 moles / 0.8630 = 1

N:  0.8630 moles / 0.8630 moles = 1

Cl: 1.726 / 0.8630 = 2

The empirical formula is PNCl2

The empirical formula has a molar mass of 115.88 g/mol

The compound has a molar mass of 579.43 g/mol

579.43/115.88 = 5

The molecular formula is 5*(PNCl2) = P5N5Cl10