Question

A compound of phosphorus and sulfur used in match heads contains 56.29% P and 43.71% S. The molar mass corresponding to the empirical formula of this compound is:

A. 188.1 g/mol
B. 220.1 g/mol
C. 93.94 g/mol
D. 251.0 g/mol

Answer 1

The empirical formula of the compound containing phosphorus and sulfur used in match heads is P4S2. The molar mass of the empirical formula is 220.1 g/mol.

Step-by-step explanation:

The compound of phosphorus and sulfur used in match heads contains 56.29% P and 43.71% S. To find the empirical formula, we need to convert the percentage composition into mole ratios. Assume we have 100 grams of the compound, which means we have 56.29 grams of P and 43.71 grams of S.

The molar mass of phosphorus is 31 g/mol and the molar mass of sulfur is 32 g/mol. To find the number of moles, we divide the mass of each element by its molar mass. Using this information, we can calculate the empirical formula.

Now, let's find the mole ratios. Divide the number of moles of each element by the smallest number of moles. Round to the nearest whole number to get the empirical formula. In this case, the empirical formula is P4S2.

To find the molar mass of the empirical formula, we need to calculate the sum of the molar masses of each element in the formula. The molar mass of phosphorus is 31 g/mol and the molar mass of sulfur is 32 g/mol. Multiplying the subscripts in the empirical formula by their respective molar masses and summing them up, we get a molar mass of 220.1 g/mol, which corresponds to option B.