The first one is B because it’s gonna be positive if it’s gaining energy
Boyle's law p1V1=p2V2
p2=(p1V1)/V2
p2=(205*10^3 Pa * 4*10^-3 m^3 ) / (12*10^-3 m^3)
p2= 68333 Pa
Number of moles = volume / (molar volume)
Molar volume at stp = 22.4 dm^3
Volume = no of moles × molar volume
= 0.987 × 22.4
= 22.1088 dm^3
= 22108.8 cm^3
Hope it helped!
a) synthesis- or combination- reaction
