Which amongst the following has more number of atoms, 11.5 g of sodium or 15 g of calcium ? How?


#1

23 g of Na =1 mole
11.5 g of Na = 11.5/23 mole
Now, 1 mole of Na contains
= 6.022 x 10^23 atoms

11.5/23 mole of Na contains
= 6.022x10^23 x 11.5/ 23mole
= 3.011 x 10^23 atoms

40 g of Ca =1 mole
15 g of Ca = 15/40 moles

Now, 1 mole of Ca contains
= 6.022 x 10^23 atoms

15/40 mole of Ca contains
= 6.022 x 10^23 x 15/40
= 2.258 x 10^23 atoms

Na has more number of atoms.