How many moles of Oxygen (O) are in 20.15x10^25 atoms of O?

334.6 moles of O, 167.3 moles as O2

Explanation:

20.15x10^25/6.02214076x10^23 = 334.6 as atoms, 167.3 as O2

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2