Answer: The new pressure is 0.39 bar
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,
[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 1.2 bar
[tex]P_2[/tex] = final pressure of gas = ?
[tex]V_1[/tex] = initial volume of gas = 20.0 ml
[tex]V_2[/tex] = final volume of gas = 80.0 ml
[tex]T_1[/tex] = initial temperature of gas = [tex]25^oC=273+25=298K[/tex]
[tex]T_2[/tex] = final temperature of gas = [tex]120^oC=273+120=393K[/tex]
Now put all the given values in the above equation, we get:
[tex]\frac{1.2\times 20.0}{298}=\frac{P_2\times 80.0}{393}[/tex]
[tex]P_2=0.39bar[/tex]
The new pressure is 0.39 bar
