Question

A 50.51g sample of a compound made from phosphorus and chlorine is decomposed. Analysis of the products showed that 11.39 g of phosphorus atoms were produced. Answer using three significant figures.

What is the percent by mass of phosphorus?
%

What is the percent by mass of chlorine?
%

Answer 1

mass of phosphorus (P) = 11.39g

mass of chlorine (CL) = mass of compound - mass of phosphorus

50.51 - 11.39 = 39.12g

atomic mass of P : CL = ( 11.39 / 31 ) : (39.12 / 35.5) = 1 : 3

mass of p% = 11.39/31 * 100 = 36.7 %

mass of CL% = 39.12 / 35.5 * 100= 110 %

empirical formula :- PCl3

Answer 2

The percent by mass of phosphorus is 22.5%.

The percent by mass of chlorine is 77.5%.

Step-by-step explanation:

Amount of compound made from phosphorus and chlorine, M = 50.51 g

Amount of phosphorus atoms were produced,x = 11.39 g

`\%=\frac{\text{Amount of element's atoms in compound}}{\text{Amount of compound}}* 100`

The percent by mass of phosphorus:

`\%=(x)/(M)\tims 100=(11.39 g)/(50.51 g)=22.5\%`

The percent by mass of chlorine:

= 100% - (percent by mass of phosphorus)%=100 % -22.5% = 77.8 %