In 18 grams of water (H2O), number of molecules is:

(A) 6.02 x 10^23
(B) 6.02 x 10^24
(C) 6.02 x 10^30
(D) 6.02 x 10^34

Answer: (A) 6.02 x 10^23
In 18 grams of water (H2O), number of molecules is 6.02 x 10^23.