Answers by visitors named: Chemgnam Style

(a) From 530 to 570. (d) 0.41 any ideas for b)and c) ?

maybe by Shakti: 0.52*(4.9*10^-9)*(concentration in mole/0.52) then multiply solution (molar flow rate) with molar mass of helium. solution should be effusion rate. its just a suggestion, all other interested are invited to post their opinion/formula