Question

A quantity of an ideal gas is collected in a graduated tube over the mercury in a barometer type arrangement. the volume of gas at 20°c is 50ml and the level of mercury is 100mm above the outside of the mercury level. the atmospheric pressure is 750mm. the volume of gas at stp is​

Answer 1

Answer : The volume of gas at STP is​ 6.21 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,

`(P_1V_1)/(T_1)=(P_2V_2)/(T_2)`

where,

`P_1` = initial pressure of gas = 100 mmHg

`P_2` = final pressure of gas = 750 mmHg

`V_1` = initial volume of gas = 50 mL

`V_2` = final volume of gas = ?

`T_1` = initial temperature of gas =
`20^oC=273+20=293K`

`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:

`(100mmHg* 50mL)/(293K)=(750mmHg* V_2)/(273K)`

`V_2=6.21mL`

Therefore, the volume of gas at STP is​ 6.21 mL