Chem question see pic above

0.72 atm

Explanation:

638 mL = 0.638 L

6.17 +273.15 =279.32 K

0.85 atm

780.50 mL = 0.78050 L

15.94 +273.15= 289.09 K

P2 -?

P1V1/T1 = P2V2/T2

0.85 atm*0.638L/279.32K = x *0.78050L/289.09 K

x = 0.85 atm*0.638L*289.09K/(279.32K *0.78050L)=0.72 atm

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.