Question

Question 3 1 pts What is the theoretical yield (in grams) of phosphorus pentachloride when 3.39 g of phosphorus reacts with 28.4 g of chlorine according to the following reaction: P415) + 10 Cl2 → 4 PC15 (1) Use the correct number of significant figures, fill in! the number ONLY! Question 4 6:02 PM 10/28/2019 1 D a 1x

Answer 1

Molar mass of P4 = 123.88 g/mol

mass(P4)= 3.39 g

use:

number of mol of P4,

n = mass of P4/molar mass of P4

=(3.39 g)/(1.239*10^2 g/mol)

= 2.737*10^-2 mol

Molar mass of Cl2 = 70.9 g/mol

mass(Cl2)= 28.4 g

use:

number of mol of Cl2,

n = mass of Cl2/molar mass of Cl2

=(28.4 g)/(70.9 g/mol)

= 0.4006 mol

Balanced chemical equation is:

P4 + 10 Cl2 ---> 4 PCl5

1 mol of P4 reacts with 10 mol of Cl2

for 2.737*10^-2 mol of P4, 0.2737 mol of Cl2 is required

But we have 0.4006 mol of Cl2

so, P4 is limiting reagent

we will use P4 in further calculation

Molar mass of PCl5,

MM = 1*MM(P) + 5*MM(Cl)

= 1*30.97 + 5*35.45

= 208.22 g/mol

According to balanced equation

mol of PCl5 formed = (4/1)* moles of P4

= (4/1)*2.737*10^-2

= 0.1095 mol

use:

mass of PCl5 = number of mol * molar mass

= 0.1095*2.082*10^2

= 22.79 g

Answer: 22.8 g