Question

The effect of chlorofluorocarbons (such as CCl2F2(g)) on the depletion of the ozone layer is well known. The use of substitutes, such as CH3CH2F(g), for the chlorofluorocarbons, has largely corrected the problem. Calculate the volume (in L) occupied by 14.6 g of each of these compounds at STP. (a) CCl2F2(g) L (b) CH3CH2F(g) L

Answer 1

Explanation:

a) Pressure of the gas a STP = P = 1 atm

Temperature f the gas at STP = T = 273.15 K

Moles of given gas i.e. $CCl_2F_2$ at STP = n

$n=\frac{14.6 g}{121 g/mol}=0.1207 mol$

Volume occupied by the given gas = V

$PV=nRT$  (ideal gas equation)

$V=\frac{nRT}{P}=\frac{0.1207 mol\times 0.0821 atm l/mol K\times 273.15 K}{1 atm}=2.71 L$

The volume occupied by 14.6 grams of $CF_2Cl_2$ is 2.71 liters.

b) Pressure of the gas a STP = P = 1 atm

Temperature f the gas at STP = T = 273.15 K

Moles of given gas i.e. $CH_3CH_2F$ at STP = n

$n=\frac{14.6 g}{48g/mol}=0.3042 mol$

Volume occupied by the given gas = V

$PV=nRT$

$V=\frac{nRT}{P}=\frac{0.3042mol\times 0.0821 atm l/mol K\times 273.15 K}{1 atm}=6.82 L$

The volume occupied by 14.6 grams of $CH_3CH_2F$ is 6.82 liters.