Question

12.
A bacterial culture isolated from sewage produced 41.3 ml of
methane, CH, at 31°C and 753 mm Hg. What is the volume of
this methane at STP?
e a=
e the
– for

Answer 1

Answer : The volume of methane gas at STP is 36.75 mL

Explanation :

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 753 mmHg

$V_1$ = initial volume of gas = 41.3 mL = 0.0413 L

$T_1$ = initial temperature of gas = $31^oC=273+31=304K$

$P_2$ = final pressure of gas at STP = 1 atm = 760 mmHg

$V_2$ = final volume of gas at STP = ?

$T_2$ = final temperature of gas at STP = $0^oC=273+0=273K$

Now put all the given values in the above equation, we get:

$\frac{753mmHg\times 0.0413L}{304K}=\frac{760mmHg\times V_2}{273K}$

$V_2=0.03675L\approx 36.75mL$

Therefore, the volume of methane gas at STP is 36.75 mL