The same as alittle molecule but it would be in a mase quantity...
Atomic number is 8 and atomic mass is taken as 16 amu
Answer:
(a) 
(b) 
Explanation:
Hello,
In this case, since the both gases behave ideally, with the given information we can compute the moles of He in A:

Thus, since the final pressure is 3.60 bar, we can write:

The moles of helium could be computed via solver as:

Or algebraically:

In such a way, the volume of the compartment B is:

Finally, he mole fraction of He is:

Regards.
Order.
Hope this helps! :)