Question

How many molecules are in 15 grams of Oxygen gas?

A. 2.8 x 10 23 molecules of O2
B. 2.9 x1026molecules of O2
C. 2.5 x 10-24 O2
D. 9.03 x 1024 molecules of O2

Answer 1

Number of grams in 1 mole = 6.23 * 10^23
Now, in 15, it would be: 15 / 6.23 * 10^23 = 2.5 * 10^-24 moles (approx.)

In short, Your Answer would be Option C

Hope this helps!