How many moles are in 1.06 x1020 atoms of iron? Express your answer to three significant figures and in correct scientific notation.

Question

If someone can show me the steps so I can solve on my own. I've been struggling with online classes just want to make sure my equations are right. I solved like this but I'm unsure if it is right. Thank you in advance!

(1.06 x10^20) / (6.02 x 10^23) x 1 = 0.259moles.

Answer 1

Hello, Kj,

Your logic is correct, but please check the final calculation. 1 mole of iron is 6.02 x 10²³ atoms of iron. So 1.06x10²⁰ iron atoms is less than a mole. The division is the correct method to calculate moles of iron:

(1.06x10²⁰ iron atoms)/(6.02 x 10²³ atoms of iron/mole)

The atoms of Fe unit cancels and the moles Fe goes to the top. This will give you moles of iron in 1.06x10²⁰ iron atoms. But check the division.

Just doing a simple 1/6 = 0.167 and 10²⁰ /10²³ (result is 10^-3 ) gives a number far less than what you indicated. I get 0.000176 moles.

Otherwise, good work,

Bob