Explanation:
Using the Combined Gas Law, which is:
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
(With [tex]P_1,V_1,T_1[/tex] being initial pressure, volume and temperature; and
[tex]P_2,V_2,T_2[/tex] being the new values)
We can move the units around in order to solve for [tex]P_2[/tex], which would look like this:
[tex]P_{2} =\frac{P_1V_1T_2}{V_2T_1}[/tex]
Then we convert the Celsius temperature to Kelvin:
[tex]25[/tex] °[tex]C[/tex] = [tex]289[/tex] [tex]K[/tex]
[tex]100[/tex] °[tex]C[/tex] = [tex]373[/tex] [tex]K[/tex]
And now, we plug in all of the values and solve, with volume remaining as a constant:
[tex]P_{2} =\frac{(1.00 atm) (20.0 L) (373 K)}{(20.0 L) (298 K)}[/tex] [tex]=[/tex]
[tex]1.25[/tex] [tex]atm[/tex] or [tex]127[/tex] [tex]kPa[/tex]
