How many moles are in 2.91 × 10²² atoms of He?

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

We have the final answer as

Hope this helps you

its first and third is your answer i did the qustion the fourth isnt right