Question

How many moles of O atoms are in 2.1 x 10^25 N2O5 molecules?

Answer 1

Answer:

0.15

Explanation:

for this problem, you need the avogadro number. it's a constant. the avogadro number tells you how many particles there are in a mole. that's why a mole is called the chemists dozen. 1 mole = 6.02 x 10^23, which is the avogadro number.

n(amound of moles)=m(mass) / mw(molecular weight)

first: (2.1 x 10^25) x 1/6.022 x 10^23 = 34.8721355 approx 34,87 moles of N2O5.

next, lets find the molecular weight of N2O5. 2n + 5o= 2(14) + 5(16)=108 ,s your molecular weight. however, that's for one mole. so you have to determine the weight for the current one. so:

34.87 mol x ( 108 grams/1 mol) = 3765,96 grams of N2O5

now comes the final battle, you have found that you have 3765,96 grams of N2O5 for 34,87 moles. to find the mole amount of o, simply  use it's molecular weight. (16)

so 16 grams x (34,87 moles / 3765,96 grams)

=0.14814815 round that up to a 0.15 and you should be good to go.