The weight of a molecule of the compound C60H122 is 1.4 × 10–21g.
Explanation :-
Molecular weight of C60H122 = 12 × 60 + 122 × 1 = 720 + 122 = 842
∵ 6 × 1023 molecule C60H122 has mass = 842 g
∴ 1 molecule C60H122 has mass 842 / 6 × 1023 = 140.333 × 10–23 g = 1.4 × 10–21 g.