Question

A 2.95 g sample of an unknown chlorofluorocarbon (an organic compound containing chlorine and fluorine) is decomposed and produces 581 mL of chlorine gas at a pressure of 752 mmHg and a temperature of 298 K. What is the percent by mass of chlorine in the chlorofluorocarbon?

Answer 1

Answer:

mass percent of chlorine is 56.5%

Explanation:

Given data:

Volume V = 581 mL = 0.581 L

Pressure P = 752 mm of Hg = 752/760 = 0.9894 atm

Temperature T = 298 K

Molar gas constant R = 0.08206 atm.L/mol.K

from Ideal gas equation we have following relation

PV = nRT solving for n

$n = \frac{PV}{RT}$

$n = \frac{0.9894 \times 0.581}{0.08206 \times 298}$

n = 0.0235 mole

mas of $Cl_2$  = moles × molar mass of $Cl_2$

                        $= 0.0235 \times 70.906 = 1.66 g$

Mass percent of chlorine  $=  \frac{mass\ of\ Cl}{mass\ of\ sample}$

$=\frac{1.66}{2.95} = 0.565 = 56.5 %$