Combined gas law
[tex]\text{ P}_1\text{V}_1\text{T}_2\text{ = P}_2\text{V}_2\text{T}_1[/tex]
T1= 200°C + 273.15 = 473.15 K
P1 = 101.3 kPa
V1 = 5L
T2 = 100°C + 273.16 = 373.15 K
V2 = 7L
Solve for P2
[tex]\text{ P}_2\text{ =}\frac{\text{ P}_1\text{ V}_1\text{T}_2}{\text{ V}_2\text{ T}_1}=\text{ }\frac{101.3\text{ kPa }\times\text{ 5L }\times373.15\text{ K}}{7\text{ L }\times473.15\text{ K}}=\text{ 57.1 kPa}[/tex]
The answer is 57.1 kPa
