Question

Chlorine gas is added to a large flask to a pressure of 1.85 atm, at a temperature of 322 K. Phosphorus is added, and a reaction takes place using all of the Cl2 gas. When the reaction is complete, the yield of PCl5 is measured at 118 grams. Calculate the Volume of the flask (in Liters): g

Answer 1

Answer:

The volume of the flask is 20.245 litres .

Explanation:

We are given with following information-

$PV=nRT$ -------- 1

where R =$0.0821L.atom/mole.K$

Molar mass of $PCl_5=208.22g/mole$

The given chemical equation is -

$2P _(_s_)+5Cl_2 _(_g_)\rightarrow2PCl_5 _(_s_)$ --------- 2

Now , calculation -

Mass of $PCl_5$ formed = 118g

Molar mass of $PCl_5$ = $208.22g/mole$

      Mole = $\frac{mass (g)}{molar mass}$

Therefore , moles of $PCl_5$ formed = $\frac{118}{208.22}$

     From equation 2 , we get to know that ,

 2mole $PCl_5$ formed from 5 mole $Cl_2 _(_g_)$

Therefore , $\frac{118}{208.22}$ mole $PCl_5$ formed from $\frac{5}{2} \times\frac{118}{208.22}$ mole $Cl_2 _(_g_)$

Moles of $Cl_2 _(_g_)$ used =$\frac{5\times118}{2\times208.22} mole$

R= $0.0821L.atom/mole.K$

Pressure (P)= 1.85atm

Temperature (T)= 322K

Moles of  $Cl_2 _(_g_)$ (n)= $\frac{5}{2} \times\frac{118}{208.22}$ moles

Applying  the formula above in 1 equation , that is

PV = nRT

putting the given values -

$1.85 \times V=\frac{5}{2} \times\frac{118}{208.22}\times0.0821\times322$

 V = 20.245 litres.

Hence , the volume of the flask is 20.245 litres .