Question

The number of atoms present in one mole of an element is equal to Avogadro number. Which of the following element contains the greatest number of atoms?
(a) 4 g He
(b) 46 g Na
(c) 0.40 g Ca
(d) 12 g He

Answer 1

I hope this helps, thank you.

Answer 2

12 Grams Of Helium

Calculating the Avogadro number of all the elements which are mentioned:

Formula used for calculating Number Of Atoms:

No of Atoms = Avogadro number x No of moles

Formula used for calculating Number Of Moles:

No of Moles = Weight of Atom / Mol. Weight

(a) 4 g of Helium

= 4 / 4

= 1 mole

(b) 46 g of Sodium

= 46 / 23

= 2 moles

(c) 0.40 g of Calcium

= 0.40 / 40

=0.01 mole

(d) 12g of Helium

= 12 / 4

= 3 mole

Therefore, 12 grams of Helium atoms has the greatest number of atoms comparing to all the other elements which are mentioned here.