Protons and Neutrons is what determines the atomic mass. I cannot further explain this answer, however, I hope I helped!
The answer is b because if you’re fan is blowing and you spend it the opposite way, the air will be cooler
The ratio of the diffusion rate of Cl2 and O2 is 1.5
calculation
rate of diffusion Cl2/ rate of diffusion O2 =√ molar mass of Cl2/ molar mass of O2
molar mass of Cl2 = 35.5 x2 = 71 g/mol
molar mass O2 = 16 x2 =32g/mol
that is rate of diffusion Cl2/ rate of diffusion of O2 =√ 71/ 32= 1.5
