Calculate the no. Of Na2CO3 molecule and no. Of oxygen atoms in 21.2g of Na2CO3

Please!!!!!

For this we first need to find number of mole of Na2Co3,then mole of oxygen

Now mole=given weight /molecular weight

Here molecular weight of Na2Co3 =2 ✖ 23+12+16 ✖ 3=106

So mole of Na2Co3 =21.2/106=0.2

Now, 1mole of Na2Co3 contains 3

Mole of oxygen so

Mole of oxygen =3 times 0.2 =0.6

Now for numbers of oxygen atom we just multiply this mole with avogadro number.

Avogadro number :-6.022 ✖ 10^23

So finally total atoms Of oxygen =

6.022 ✖ 10^23 ✖ 0.6=
3.61 ✖ 10 ^23