Answer: 0.859 atm
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 (STP) = 1 atm
[tex]P_2[/tex] = final pressure of gas = ?
[tex]V_1[/tex] = initial volume of gas (STP) = 10.0 L
[tex]V_2[/tex] = final volume of gas = 12.5 L
[tex]T_1[/tex] = initial temperature of gas (STP) = 273K
[tex]T_2[/tex] = final temperature of gas = [tex]20.0^0C=(273+20)K=293K[/tex]
Now put all the given values in the above equation, we get:
[tex]\frac{1\times 10.0}{273}=\frac{P_2\times 12.5}{293}[/tex]
[tex]P_2=0.859atm[/tex]
Thus at 0.859 atm , same sample have a volume of 12.5 L and a temperature of [tex]20.0^0C[/tex]
