Question

Two different compounds, each containing only phosphorus and chlorine, were decomposed into their constituent elements. One produced 0.2912 g P for every gram of Cl; the other produced 0.1747 g P for every gram of Cl. Show that these results are consistent with the law of multiple proportions.

Answer 1

Answer:

Dalton's law is fulfilled, since the elements in each compound of the example are related to each other in different proportions forming two different compounds;  so for case a) and b) you have 15.54% and 9.323% P respectively for each compounds,  that are equivalent to 0.2912 g P for every g Cl and the other produced 0,1747 g P for every g Cl.

Explanation:

Dalton's Law ( law of multiple proportions):

When two or more elements combine to give more than one compound, a variable mass of one of them joins a fixed mass of the other, and the first is related to canonical and indistinct numbers.

• P + Cl ↔ PCl

a) for the compounds A:

⇒ 0.2912 g P / gCl * ( 35.45 g CL / mol CL) * ( mol Cl / mol PCl ) * ( mol PCl / 66.427 g PCl ) = 0.1554 g P / g PCl

⇒ % P = 0.1554 * 100 = 15.54 %

b) for the compunds B:

⇒ 0.1747 g P / g Cl * ( 35.45 g Cl / mol Cl ) * ( mol Cl / mol PCl ) * ( mol PCl /  66.427 g PCl ) = 0.09323 g P / g PCl

⇒ % P = 9.323 %