Question

0.578 g of phosphorus and 0.650 g of chlorine were all allowed to react. After the reaction was complete, all of the chlorine had been consumed, but .389 g of phosphorus remained. divide each number of moles of the reactant consumed by the smaller number of moles. round your result to the nearest whole number ratio to obtain the empirical formula. What is the formula used? and what is the empirical formula?

Answer 1

Answer: According to the given informations the balance equation of the question is like :

  P4 + 10 Cl2 → 4 PCl5

initially we have 0.578g 0.650 -

Here we can see that 1 mol P4 will produce 4 mol PCl5

Now, according to question 0.389 g of phosphorus is remained means

reacted amount of Phosphorus is = 0.578 - 0.389 = 0.189 gram

Now 1 mol P4 will prodece = 4 mol Pcl5

means 123.89 g will produce = 208.24 * 4 = 832.96 g of Pcl5

then 0.189 g of P4 will produce = 1.27 g of PCL5

Now the number of moles of P= 0.189 / 30.9 = 0.0061165 mol

and the moles of Chlorine = 0.650 / 35.45 = 0.018335 mol

now dividing all these moles with the smallest number of moles of p we get

P = 1

Cl = 2.99 = 3

Hence the empirical formula is PCl₃.

This is all about the given question thank you :)