III.
Ar = (c1%xA1 + c2%xA2 + ... + cn%xAn)/100
avem:
²⁰Ne (89,97%) , ²¹Ne (0,76%) , ²²Ne (9,27%)
=> Ar = (89,97x20+0,76x21+22x9,27)/100 = 20,193 u.a.m.
IV.
1 mol S .................. 32g S ..................... 6,022x10la23 atomi
4g S ....................... n = 7,53x10la22 atomi S
