Question

A sample of gas occupies 250 mL under laboratory conditions

of27oC and 740 mmHg pressure. What is the volume
atstandard temperature and pressure conditions?

Answer 1

Answer : The volume at standard temperature and pressure conditions is, 222 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 = 740 mmHg

`P_2` = final pressure of gas = 760 mmHg

`V_1` = initial volume of gas = 250 mL

`V_2` = final volume of gas = ?

`T_1` = initial temperature of gas =
`27^oC=273+27=300K`

`T_2` = final temperature of gas =
`0^oC=273+0=273K`

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

`(740mmHg* 250mL)/(300K)=(760mmHg* V_2)/(273K)`

`V_2=221.5\approx 222mL`

Therefore, the volume at standard temperature and pressure conditions is, 222 mL