Q47) Rearrange the following ( I to IV ) in the order of increasing masses and choose the correct answer from (a), (b), (c) and (d) ( Atomic mass: N=14, O=16, Cu=63)
I. 1 molecule of oxygen
II. 1 atom of nitrogen
III. 1×10-10 g molecular weight of oxygen
IV. 1×10-10 g atomic weight of copper
[ IIT 1993]


I. 1 molecule of oxygen=32 / NA=5× 10-23
II. 1 atom of N=14/NA=2.3×10-23
III. 10-10g mol wt. of oxygen=10-10 ×32=3.2×10-9g
IV. 10-10g atom of copper=10-10×63=6.3×10-9Answer: (a)