Question

A gas inside a piston initially has a pressure of 1.2 bars at temperature of 25 degree C and volume of 20.0 mL. If temperature is increased to 120 deg C and the piston expands to a volume of 80 mL, what is the new pressure

Answer 1

Answer: The new pressure is 0.39 bar

Step-by-step 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 = 1.2 bar

`P_2` = final pressure of gas = ?

`V_1` = initial volume of gas = 20.0 ml

`V_2` = final volume of gas = 80.0 ml

`T_1` = initial temperature of gas =
`25^oC=273+25=298K`

`T_2` = final temperature of gas =
`120^oC=273+120=393K`

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

`(1.2* 20.0)/(298)=(P_2* 80.0)/(393)`

`P_2=0.39bar`

The new pressure is 0.39 bar